I made a list of components that I think might fit the bill.
Just some feedback on building the solution instead of buying something cheap off-lease that might not fit, building something will probably increase the cost by 5x.
I have that exact case on my Intel pfsense Router build -- its nothing fancy but fine & small, manual sucks.
I see you noticed its pretty low profile,
where you might face some difficulty is if you check the manual it has extremely limited vertical space between CPU and amounted 3.5" HDD (
on page 15 it shows approximately 37mm of clearance from a mounted 3.5" HDD and CPU because the 3.5" hard drive suspends above the CPU from a bracket), and that cooler is 37mm which means it wont be able to breath at all provided it even fits as you have no extra margin in vertical mm's.
For that ML05 build you might have to go with 2.5" HDD (not SSD), as those can be mounted above the CPU or (better) in front of the power supply in that case (2 drives).
You might also look at the ML07 version (or FTZ01) which is fractionally larger and modestly deeper, but both have a dedicated position for 3.5" HDD that won't cramp your CPU cooler so much.
Just get discount RAM, you don't need anything "gamery", basic Crucial/Kingston/Micron ram without heat spreaders or low CL isn't worth even $5 more imho.