This build has been an ongoing ordeal, it has been transplanted to the third case now. When I initially bought the meshify and strix motherboard I had my Gaming X RX 580, soon after I purchased a BIOS modded 480 and paired them in crossfire. Benchmarking performance was great but real-world performance was worse in most cases. I eventually broke down and purchased the Vega56 on sale and I'm glad I did.
The X470 Strix motherboard's BIOS is awesome! Easy to navigate and tons of options you'll probably have to look up to figure out. The board easily keeps my R7 1700 at 3.9ghz at 1.38v. Before I was using a cheap MSI B350 board and it was unstable at 3.9 @1.40. VRMs matter!
The Meshify C was a complete dream to work in coming from an InWin 301 setup. Absolutely no complaints about the case. Thermals are excellent, all fan slots are utilized with the exception of the floor-mounted one (which requires removal of the HDD cage). In order to fit 3 fans in the front, you need to remove the two screws at the front of the PSU shroud and remove the cover. You can then slide the HDD cage forwards to close the gap to the fan at the bottom once installed. This makes for a much cleaner look than removing the cage entirely as all the cables from the PSU are routed there.
I've got to say I'm a huge fan of the Coolermaster ML240R. It looks amazing and AURA sync works straight from the 3-pin header, meaning no extra control modules cluttering everything up. I run a constant fan speed of 2000rpm, and have not seen temps over 60 degrees. It's a little loud but not annoying, very easy to tune out.
The Strix Vega56 is HUGE. Not a lot of sagging but it is there. There would be no way to run a radiator at the front of the case with this card. However, the space between the PSU shroud and GPU has a constant supply of fresh air which results in awesome thermals and low GPU fan speeds.