Idletemps sadly mean nothing - You have to look at the temps under your typical workload. These CPUs need lowered tdps in any case with these coolers - they are just not a good choice for such a small air cooled system.
I think adding external components defeats the pupose of a case. I would prefer switching up to a slightly larger case like the A4-H2O or C4-SFX instead of having anything dangling outside of the case.
I prefer the A4-SFX because i like the round radians above 90° edges, the minimalistic frontpanel (just power switch and usb-c port) in front and of cause for the small footprint. Anything I/O related is taken care of at I/O backplate of the motherboard.