Weir to vent distance and venting options - IPC 2015

I have a new bathroom which plumbs the shower into the main stack via a 2” PVC pipe.
My understanding is that the distance from the trap weir to a (in this case wet) vent can be up to 8”.

My shower weir-to-vent distance is about 7’9", properly graded at 1/4” per foot, so it would appear I am in the clear as far as siphoning and any vent issues go. However, I am hearing different takes on whether my long drain constitutes a trap arm which should not be more than 5’ in length.

Just in case, I installed a separate extra vent (pointed to in red) to the right of the p-trap, that goes through the wall in the shower and into the attic, where it terminates in a AAV (Studor valve), which in itself is legal per my local regulations (and IPC 2015).

My questions:

1. Is my sub-8-foot weir-to-vent plumbing to code as far as IPC 2015?
2. If it is not, will my extra vent be an IPC 2015-permissible way to vent the shower?
3. I don’t like the idea of having metal straps rubbing against the PVC piping, so I am inserting rubber between them (see example photo). Is there anything wrong with that?