I'm going to go with the heatsink sucks, it was a fluke/bad part...or you did it wrong.
I've moved my noctuas around various AM# and FM1 boards with zero issue, and AMD's own docs have the sockets as exactly the same regarding heatsinks. (in other words, if an ODM heatsink was validated to be put in AMD's own branded boxes for # TDP AM2/3 cpus, it was accepted for FM1)
For your #2 there are some pdfs you can dig up on AMD's site.
E5 1680v2 8c16t 4.5Ghz - "Yes Virginia, there were unlocked xeons"
E5 2696v4 22c44t 2.2~3.7Ghz Because Reasons™
TR 1950x 16c32t - taking my sweet time finishing up the build