Ooh. Ooh! Interesting thought. What a tantalizing possibility!
IIRC, the agreement was that when the Homeworlds invaded, the Adders wouldn't go through the HHOZ, so that's not actually what I'd call an alliance, at least no more than the 'alliance' the Hellions and Horses had when they invaded the Falcons. Politically that could also be very dangerous for the Adders, champions of the Bastion movement, shown to have secret dealings with a Tainted, Abjured Clan, I'm sure they'd catch all kinds of heat at home for that revelation if it ever came out.
It also seems like we are a good, long while before the Wolves and the Horses get a chance to fight, so I'm also hoping there is some sort of further developments with this aspect of the story before then.