I am also looking to join the inverted ILS approach club, and have a
question not covered by the previous research into this subject.

Should I expect any issues with extending landing gear whilst inverted
(Cessna 172RG) either with mechanical deployment or aerodynamic
aircraft behavior?

I had considered waiting until I flip out, but I'm a stickler for
doing  pre-landing checklists 'by the book'.

eppy---as the gear doors open, drag increases slightly.  The nose will
respond.  Plan on PIO.

Good luck!
ron