So maybe a dedicated circuit can be used to plug amps directly into and then have Power isolator connected to a separate Circuit for everything else.
Yes. One dedicated 20A circuit for the two amps and one dedicated 20A circuit for your front end stuff. Amps plugged directly into the wall. No comment on whether to use the power isolator for your front end gear.
I have owned some pretty big monoblock amps (both Class A and AB) but none where a single 20A circuit would not have provided enough power, although I suspect there are a few monster amps out there. @erik_squires asked a good question as to the power consumption of your amps, and an easy way to gauge would be to look at the fuse size to each. If 8A or below, then one circuit at 20A should be enough.