Excuse the ignorance on terms, when you say combo, I believe that means a curved wye?
Your picture shows a combo. It's called that as it is a one piece combination wye plus 45. You can always use a wye plus a 45 where you need a combo, but that would take up more room.
That wouldn't have a clean exit out of the drywall.
Either the perspective is very weird, or you're showing a 2" combo.
Since I'm raising the fitting for the p-trap anyway, would the picture below be ok?
I don't understand what that picture means, what you intend it to show as a proposed configuration.
A trap arm can't drop more than one pipe diameter before being vented, so if you want the two trap arms to join a single san-tee on the stack, you'd need a horizontal combo to combine the trap arms.
You can put two separate san-tees on the stack, one on top of the other (they make street san-tees), then you could have two separate trap arms at different elevations, and each trap arm could enter the wall via a quarter bend as usual. Obviously your two traps would end up at different elevations.
Or you could put a double fixture fitting in the wall horizontally in between both traps, with the drain dropping down before jogging horizontally to join your existing stack. Likewise the vent off the double fixture fitting would rise up at least 6" above the fixture flood rims before jogging horizontally to join your existing stack. And the stack between those connections could disappear, i.e. each connection to the stack could be a quarter bend.
Cheers, Wayne