After a few hours of work.... it smells good. I bought a broken Tab Mini C on eBay (the front glass was broken, but not the e-ink screen).
On the left, my original front glass. On the right, my tab Mini C frame with the replacement screen.
I managed to remove the shards and clean the screen. Need some polishing of the touch panel as removing shards made a lot of tiny scratches on the panel.
But... everything is functional. LOCA glue + UV lamp ordered, it'll arrive on Thursday. Seems like after all I may save my Tab Mini C.
If successful, I'll create a step by step disassembling and screen replacement guide (which I DO NOT recommend to anyone. You'll have to be crazy or desperate to attempt it. The risks are way too high to end up with two broken devices).