My first questions are, if I’d run an H90 in Dual mode, could I use inputs and outputs 3 and 4 as I’m currently using my 2nd H9 above in my FX loop?
Yes.
Could I use input/output 1 then as I’m routing my first H9 above in pre/post mode? Essentially using input/output 1 for preamp effects, and input/outputs 3 and 4 for post/FX loop effects?
Yes.
Finally, if the above routing would work for my purposes, would I be limited by the H90 with only effect A in front/pre and effect B in post? Or, could I still route effects A and B both in post or pre if I wanted to?
Other than having an effect in Path A and another in path B, it is possible to have Programs that have both effects in front (Path A) and other Programs that place the both effects in the loop (Path B).
Could I still use both FX pre or post, or am I limited at that point to 1 pre, 1 post?
You can put both FX in pre or post.
