my system has only 1 casefan (in front of the HDDs) at 600 RPM ... external radiator so no additional airflow whatsoever
CPU, GPUs and motherboard VRM are watercooled, but memory & chipset aren't
case temps are around 4c above ambient temps on idle, after long gaming sessions the difference is around 8c to 10c; I've noticed that pretty much all of the heat comes from the memory sticks so watercooling them would take away pretty much all the heat I guess
if I only had SSDs and also watercooled the memory & chipset I'd run it without casefans
just make sure it's not totally insulated; I've sound-proofed the front and sides, but kept the rear ventilation openings intact so that there is still a minimal amount of airflow
so yeah I think your diagram should work
I'd just open up only the left side though, as else 90% of the air from the fan would exit the case without passing any of the components ?