well that's what I thought I was going to get a corseair hx750 and my buddy got his first and a good thing to cause it was so long I just changed my mind on that order that thing was near 2'' longer than this seasonic 850x .. long story short get a ruler and check it out first and don't forget to add the wireing on the back that can be a extra inch
the H440 has a good enough amount of space for mounting any sort of power supply. As long as you're not mounting two or any other LARGE power supply the standard ATX power supply should fit perfectly fine. The HX series is bigger than others I believe so that could be a thing.
Yep! It'll fit perfectly, with plenty of room to spare.
I have the H440, the exact same model as the one you linked in fact, and I use it with a longer PSU than the XFX you have linked.
Enjoy!