Wow, page 4 and all this drama......and you don't have a leakdown test results yet?
Sorry man but you are literally spinning yourself in circles (I've done it too) until you do a leakdown and know for sure.
This was years ago so I hope nobody gets upset of I spill the beans here but let me tell you about what happened to the engine in that car years and years ago. (note, this is from memory, so do NOT take it as fact please!) It was low on compression in one cylinder. A leakdown test was performed and a few cylinders were a little low and one was really low, but it was purely leaking down from the valves. So, the head came off, it got disassembled, machined, and reassembled. Leakdown tests were the same! The same! So off came the head again and in a moment of what I can only imagine is a mix of frustration and dedicated troubleshooting, the oil pan comes off.
Oil pan off, one of the cylinders is removed for inspection. Maybe all of them? I don't know. Everything looks peachy keen super nice, no issues. I do not recall if fresh bearings & rings were used but the bottom end was then re-assembled. The head as it was was then re-installed, but as it was being torqued down they did leakdown test to try to find the problem. Leakdown was *perfect* until the final torque sequence....somewhere somehow the head had basically been warped. Even though it had been cleaned prior to this (again to what extent, idk) it still leaked on final assembly. SO they yanked the head again, had the machine shop go through it with a fine toothed lathe (lol) and re-assembled with fresh gaskets and everything--voila, a healhy 'stock' motor.
So, do a leakdown test, it really will tell you everything, as long as you are careful and do it right.
As far as the $6k goes, if you plan on doing the bottom end and even touch the head you will break $5k pretty quick. Don't skimp on anything, do it right and do it once. If your crank is in good shape, there's nothing wrong with a good 2.0! That being said, you can sell your good crank to help offset the cost of a different one.