Sounds like you have a whole mess of issues. I used to fit boots for a couple years, so maybe I can help a little bit. One thing that you might consider that can cause some major issues is your bindings. A couple quick things that can cause cramping and pressure points from your bindings-
Forward Lean- A lot of times, especially if you are not use to it, having too much forward lean can cause your tendons and your arch to constrict. Check your forward lean settings and reduce them, maybe remove all forward lean so your highbacks are straight up, then see if that makes any difference.
Binding Straps- There are all kinds of different straps nowadays, some are wider and some are skinny and each kind can cause different pressure points depending on the shape of each persons foot. I have flat feet with virtually no arch on bottom, buy the top of my foot has a high arch. I find that a narrow strap fits way more comfortably over my ankle than a big fat/wide strap and reduces pressure for my foot shape. Check your straps and maybe strap your foot into some different ones and see if you feel any extra or reduced pressure from the different bindings
You can losen your boots, just like you tried, but then when you crank down your binding staps it almost negates your lose boots.
Also, a stiff boot will be more rigid and have less "give" and so may be causeing unecessary pressure points. Try a softer boot with more flex and see if that makes any difference.
For me, BOA's don't work very well with my foot shape and the placement of my ankle bones. I find the cable cuts into my ankle bones because of where they are positioned. Plus, a steel cable will not have any "give" so may not allow your feet to circulate properly and move with your foot/ankle. Try traditional laces.
Never wear more than one pair of socks as this often causes the circulation to be cut off to your feet. The best socks I have ever used are smartwool- they keep my feet warm, but never overheated and my feet always come out dry no matter what the weather and snow is like during the day.
Don't overtighten your liner, keep it snug, but not restrictive
Let me know if any of these things help and we'll go from there
Don't just live life on the edge, jump off it!