Hello Steve,
I’m going to assume you’re using Insert Mode where In 1 is for your pre signal and I/O 3 is connected to your send/return effect loop.
1. Yes, in this configuration you may activate the chorus pedal insert on a Program basis.
2. Yes, you are able to move the position of the chorus pedal insert on a Program basis as well.
3. No. I/O 2 would not be available because inserts can only be connected to I/O 3 & 4. Input 2 would only be available if you wanted to connected stereo sources to the H90.
As to your follow-up question, correct. This configuration is only possible in Insert mode because Dual routing does not permit the use of inserts. You would have to hardware your chorus pedal to either the pre or post signal path.
