It really depends on who's making the case. My manufacturer can do 5mm distance from the bent surface to the nearest feature, 4mm for additional charge. But if you plan on making it more easy, then yes, that will certainly help.
The video said "a good 15mm" and the manufacturer's online tool doesn't accept any cutout nor punch hole within 13mm from a bending line.
The manufacture is closed during august, so I can't ask them for othet possibilities. From their process video, they can do things not allowed by their sheet metal webapp (curved cutouts, punchout cuts, etc).
I changed my design to expand the io shield cutout across the motherboard. This was the opportinity to add a CPU cutout too.
This is viewed from the back and from the motherboard. I planned to use L-bar screwed to the wood and rivet the structure to it, but I found that solution not elegant.
I added tabs at the bottom and will use threaded insert in the wooden base to create mounting point.