you could use aby for guitar signal,
and taking one of your footpedals could also go into aby and control both amps, if it's TS,
if it's TRS you could still do this by splitting that out with a hosa adapter and running those intot 2 aby's.
that would work but it would be a mess, and would cost a lot. you're talking about 2 valvestate amps, this is not worth it.
sell the 2 valvestates, get a good amp, then come back and discuss your future here with us. thx.