Well, for better or worse, this is the road I've chosen.
first, every one I've spoken to to confused as to what this stuff may be. Who knows. I tried to find a scrape away but couldn't so I went the chemical route.
Of course now I've read Mannington's instuctions and says not to use solvent based removers.
What's done is done. Can't go back now.
I used a buffer with black stripper pads and mineral spirits - a lot of it. took 6 gallons
The place stunk to high heaven but did get about 80% of the glue up. But I'm still left with a very sticky slab.
It's smooth though and in places pretty clean. I gave up on that since I knew it would take forever to completely clean the slab this way.
I talked to bostik's tech line. They were helpful. They suggested an self-leveler that doesn't need a primer (not a bostik's product).
I talk to Mapei yesterday. We went over the details and found their product Planipatch with the plus additive may work to skim coat the floor. So I bought some and put down a test area about 4'x4'. That's some sticky stuff!
Very odd consistency and had to work fast. Tomorrow I will try to remove it.
So far it looks promising although a little expensive.
What a pain. I'll try to post some pics tomorrow. Thanks for all the help so far!