Dunno about the A7RII as I have a III, but if the colors are anything alike then I actually prefer the Sony colors (and the glass) to the Canon counterparts. Never thought I'd say it as that was my main complaint after shooting the first A7 and Nikon for about a decade (with Canon mixed in in between), but I really do like the color just as much if not more than any other brand. That's subjective though, so it's really a question of whether or not you want to spend the 15 minutes emulating another brand's color science or not if you don't like it.
The Eye-AF is ridiculously good on the III (again, not familiar with the II so YMMV) and it feel like I'm almost cheating, everything is in focus...like maybe 1 out of a 100 at most are a miss. Overall it's very good AF, even in tracking although I still prefer an old 7D for fast movement.
As for studio: the EVF is more than adequate. I shoot in a dimly lit space with strobes (and no modeling lights) all the time. You just have to turn live-view preview off in settings. Worked on older NEX-6, A7, A6300, and now A7RIII. The EVF isn't the best by far (GH5 is the best I've used so far), but it's usable in studio.
All that being said, time for some possibly bad news:
Canon via an adapter won't work as good as the native glass. I haven't kept up with which ones or which adapters work best or not at all, but there's a bunch of documentation on the net that'll go into it. General consensus is it's doable to adapt EF lenses, but preferable to use Sony glass.
Also, assuming you're paying around $1600 (you said half the cost of an A7RIII) if I were you I'd look into going for an A7III instead, that way you get the 2nd best AF of the current bodies (behind only the A9, and technically stealing most of it's AF capabilities) and also the bigger batteries and joystick for AF points. The older batteries were good for 600-700 or so shots, so not the end of the world, but with the new batteries I'm getting 3000+ on a single charge. I actually go multiple shoots before I change out a battery.