Optimizing supports in this game is fairly troublesome, since there's a few characters that are fun to use but have zilch for support options (Canas), or support options that require fair amounts of grinding to get (Serra).
I'm not familiar with FE7Chaos and the class changes, but the first thing I spy with these characters is Serra's lack of choices. Serra's growth with Hector is super low (15 +1 I believe) and Hector/Lyn A usually works fairly well. Priscilla has no options (besides Lucius if you choose to use him) besides Sain, so they should probably go together. Canas also suffers, with (imo) his only decent support options are B with Pent or A with Bartre. Pent doesn't appear till more than halfway through the game and only grants a B, while Bartre grows at a mediocre rate and also isn't great as a character.
Dart/Wil/Rebecca make a good triangle, so you can mix the B supports there. Same with Raven/Lucius/Priscilla and the 3 lords.
With that being said, here is what I scrambled together;
Eliwood: Marcus A, Eliwood B
Hector: Lyn A, Eliwood B
Lyn: Hector A
Rebecca: Lowen A, Wil B
Wil: Dart A, Rebecca B
Serra Sain A, Lucius B
Priscilla:Lucius A, Sain B
Sain: Serra A, Priscilla B
Canas: :(
Lowen Rebecca A, Marcus B
Marcus: Eliwood A, Lowen B
Lucius: Priscilla A, Serra B
Dart: Wil A
Apologies for any mistakes there, just winging it!