UPDATE: No go. MSI Z270 SLI PLUS will NOT WORK w m.2 to pcie. Some other models like the A Pro are PROVEN to work but you'll notice differences in their BIOS when compared to the SLI PLUS. I knew this wouldn't work but i had to test it so others like myself would have a FOR SURE answer, not vague guesses.
I tried it every which way. The sli plus will not work with a m.2 to pcie adapter. Just get the h110 BTC+ and never look back. Now i'm stuck w 6 gpus. I could've bought the aformentioned mobo for LESS than the SLI PLUS lol. I feel dumb but, i have an answer and am willing to share the info. Hope i haved saved some headaches!