Very good points! Which is why I think khan fletcher could have pull this off. If he had defeated osis and went in on his own to defeat serpent for “
Honor” who would object to that?
Anybody who thought the Horses would gain too much from it.
Generally I don't want to argue too much on the plausibility of what appears to be alternate history fanfic for your favorite Clan. Fundamentally though I have a couple of issues with your scenario:
1. The premise that bailing out and presumably absorbing the mauled remnants of the Jags at this point the vaults the Horses to "invader Clan status" is seriously flawed. If any other Clan had thought there were serious material gains to be made by saving the Jags they would have tried. Best case what you get for your trouble is maybe a rump galaxy or so of mixed frontline and second-line troops, no fleet, no IS holdings, and Huntress with all the infrastructure already destroyed.
2. Even with good infantry/BA capturing multiple WarShips is not a simple matter and that it's more likely for most of the Serpent ships to simply be destroyed outright, with possible loss/serious damage to some of the Horses ships also, and any that the Horses did manage to capture would probably require too much repair to make any difference in the balance of power against other Clans for the immediate future.
You also seem to not be accounting at all for Task Force Bulldog. I don't know if a complete TO&E for Bulldog has ever been published but if we presume it includes the entirety of all the units which had detachments fight in the Great Refusal (see spoilers for list), then seven trinaries is grossly inadequate to take them on.
[spoiler]Units that had detachments fight in the Great Refusal:
10th Lyran Guards (AFFC)
1st Genyosha (DCMS)
Red Lancers (CCAF)
Invader Galaxy (Com Guards)
1st St. Ives Lancers (SIMC)
1st Free Worlds Guards (FWLM)
The Clan Nova Cat command Keshik also fought but it's unclear what other Nova Cat forces were part of Bulldog.[/spoiler]