So I decided that Hayate ought to be her canon age when BoD occurs, which makes her 12 in 0069. This probably has zero effect on anything involving her written thus far, as she'd be 15 in 0072. I think she won't become an actual Pilot until some time in 0073 since she had to do all the physical rehab, etc to walk again that took up time, then pilot training. Given she was somewhat mentored by Fate/Nanoha over that time and had the Wolkenritter as guardians (Shamal is not a Pilot, but ends up in Medical), the Wolkenritter served as her instructors instead of the usual training courses.
I'm actually kinda seeing a second plot arc here. First one would be 0067/0068-0069 revolving around Nanoha and Fate, and ending with the BoD fight. The second arc would start 0073, end 0075ish, and revolve more around Hayate and the Wolkenritter. For Hayate, kinda the realities of being a pilot vs the 'fanon' she's grown up with. For the Wolkenritter pilots, dealing with the issue of being her superiors while still considering her their master.
An incursion against Japan occurs in 0073 (causing Fate/Nanoha to abort their demonstration/joint-training tour in order to come back to help). Hayate's Rookie Run comes at the tail end of the brief incursion when a group of 25 kaiju move in toward a city and the Wolkenritter are deployed against them. Seven split and head for another city, so Hayate tells the others to go stop the seven and she'll handle this group. They end up leaving as she says. She Unisons with Reinforce (Eins, since there was no need to destroy/seal her), then goes Mode Set. Pops 8 cartridges and one shots the 18 kaiju using the aria "Resound, horn of the end!". The blast fries all magic sensors in 50km radius of her (and causes two drones to crash as a result).
End result: Signum, Vita, and Zafira get 2 weeks suspension with no pay and instructor certification revoked indefinitely (which is probably a pretty bad black mark on their record). Hayate gets suspending one week no pay and had her Pilot status revoked (probably a bigger black mark than the other). Shamal has Hayate occupied in medical while Nanoha informs the trio. Vita tries to argue with Nanoha over the punishments while Nanoha's chewing them out, and the trio ends up getting a month suspension. Hayate and Shamal enter as Nanoha cuts off Vita from protesting that with a threat to make it indefinite. As Nanoha leaves (slipping in a "Signum can act like a team leader for once and explain things" shot while she's at it), she stops and let's the group know that their fuck up cost Hayate a chance at a moniker then leaves. Hayate ignores Shamal's advice to let things be until tempers cool, and confronts Nanoha about the punishments at Fate's place a day or two later. She ends up getting her suspension extended to a month as well and nearly gets the Wolkenritter trio transferred to the other side of the planet.
Nanoha's anger is not so much over Hayate utterly overpowering the attack (Ragnarok is S-rank in canon. Through a ride with Mode Set and 8 cartridges... I figure it's a genuine low SSS-rank move) where she could've taken out non-combatants like civilian ships or planes or military craft before the blat ended, or aimed a few degrees down more and possible drilled a hole into the sea floor, but over the trio leaving Hayate alone. Partially because she was a rookie and needed some supervision, partially because it was a blatant violation of policies, and partially because if she missed killing any of the kaiju, she would've been killed by them before anyone could respond to assist. Yeah, Nanoha still has some issues from the Pluto Incident.
Hayate ends up getting sent to go through the regular training courses after she comes off suspension. After she graduates from there, she gets assigned a mentor in a location other than Japan. It's probably during this time frame that she puts together the TSAB/MSO joint operations concept (possibly as a thought exercise from her mentor? ... Or a mentor's friend, if she's stuck with Potter as mentor
). When Special Duty Section 6 forms in Germany, the Wolkenritter trio transfer there. Hayate ends up joining the Mid-Childa counterpart, Riot Force 6, where she meets Nanoha for the first time since 0073. Then follow along as they proceed through events involving Scaglietti. RF6 escorts Vivio to Earth via Garden of Time (first official use of Fate's "private property" for MSO business).
Major incursion occurs from the Dragon's Triangle and less so out of the Arctic rift zone. During the fighting, Hayate ends up being put in charge of the Wolkenritter, where she remains the rest of the incursion. During the chaos of dealing with the incursion, Numbers infiltrate and recover Vivio, returning her to Mid-Childa. Saint's Cradle activates and Mid-Childa ends up capitulating. The ship from the BoD incident arrives in system in time to hear what happened, and rushes to Earth to report what happened. Saint's Cradle follows, and Scaglietti and the Numbers discover that the anti-magic field is not really up to stopping overpowered Starlight Breakers, Blast Calamities, or a SSS-rank Ragnarok.
Saint's Cradle makes a (barely) controlled landing on Attu Island. The surviving Numbers and Scaglietti refuse to surrender, so SDS6/RF6 probe the wreck a bit before Nanoha decides on a faster way to get them out. Nanoha requests their surrender, and has Hayate SSS Ragnarok the wreck a few minutes after they refuse (Nanoha called it a warning shot across the bow, Hayate points out "It cleaved the front third off!", Nanoha states "It went from port to starboard in the bow section. That's technically 'across' the bow.") and repeats the surrender request with the threat of having the next warning shot go the length of the ship. Wisely, the survivors surrender this time.
And that'd probably be an arc.
--
Ahaha. You know, I sorta considered how the kaiju mess impacted the future of the SM canon. There's the obvious, such as CT probably not existing and thus no Black Moon Family to come back. Of course when it comes to time travel shenanigans a la Black Moon Family, it could still occur in an altered state. Maybe rogue TSAB mages and other people travel back in time in the hopes of stopping Vivio from eventually forming the Neo Belkan Empire with Earth as its capital and absorbing TSAB into it?
And this could lead to some definite screwing with Pluto.
"What if someone put a time turner onto the freighter in 0065 and its destruction caused all the time messes?"
Pluto sighed. "Nanoha, there's absolutely no way a time turner could end up on the freighter to start the whole series of events. Time Magic--"
"You'd like to think that."
"Like, no. Actually know, ye-- Wait. You didn't say that, did you?"
Nanoha blinked and looked past Pluto. "I kinda think I did?"
Pluto turned and saw a clearly older Nanoha, Fate, and Hayate. Future Nanoha smirked and spoke up. "Yes, a time turner was sent back onto the freighter and caused the sequence of events. Since we can't use our regular names without confusion, call me Conquest."
Future Fate waved, clearly having been blessed by the puberty fairy. "I'll be Famine."
A muttered "I'd love partake in that famine" from behind Pluto was ignored as the future Hayate finished introductions. "I don't think I need to say who I am. Chibi-me can just be Hayate for now."
Pluto simply glared at them. "In that case, where's War?"
"Oh, they're keeping the door open. Forgetting to do that leads to quantum leaps for a bit, making you feel like a Time Lord. In case you were wondering, whoever dubbed us Horsemen of the Apocalypse apparently wasn't so much 'haha funny joke' as 'touched by destiny' or something. And wouldn't you agree that screwing with Time and Space is an apocalyptic thing to do, yes? Thus is right in our hands."
Pluto settled for just growling at them and gripping her staff instead of Conquest's throat.
Four Horsemen: Conquest, riding a white horse; War, riding a red horse; Famine, riding a black horse; and Death, riding a pale horse. White Devil, Black Angel. Easy match ups there. Hayate is clearly Death (what other moniker suits someone that killed 18 kaiju in under 30 seconds?). War with its red horse could point to the Red Devil.
But the gist of the time travel reveal would be that someone in the future sent the time turner back, causing the rewrite from MGLN to MGPN. And thus, at some point post-0076 a time turner has to be sent back to the freighter to ensure the loop. I say post-0076, because that's when they discover a time turner was on the freighter, leading the investigation to eventually determining one has to be sent back in order to avoid paradox. Whether or not the visit from the future pilots sparks the investigation that results in said discovery.... As to who originally sent it back to start the loop? Maybe it was the Horsemen ("The Horsemen didn't exist yet!" "Come now, Guardian of the Gates of Time and Space. You of all people should know that some things, once made exist, have always existed.").
Also, at some point the future!pilots would get to the point of their visit and ask for the time traveling idiot criminals to be handed over so the idiots can return to their time and stand trial for various things including use of Time Magic. After all, screwing around with Time Magic is quite illegal, don'tcha know?