Nice work so far Jessy, regarding the Ab, the movie armor has no seams at the sides (CRL requirement for standard FOTK), with a expandable seam in the rear underneath the thermal detonator. Closing up the side and opening the back should solve all your issues. Not exactly sure if you could do this with this armor (possible) but if could...
Movie armor
https://imgur.com/a/Q7RvVSB
Sorry have photo issues