the latest version of Wyvern Battle Pack updated for FAF can be found here:
https://forum.faforever.com/topic/364/
(Please tell me if you find any errors)
Sadly i never got a permisson from the antares unit pack author to update/maintain his mod,
so i can't help here.
Just be sure every player has the same files and fileversion from all mods.
A desync is almost in all cases caused by different mod files or versions.