I don't think it will be. Mainly because Epic wouldn't pay.
Epic doesn't have to pay for exclusivity under their new program. Developers take home 88% of each transaction (as opposed to 70% of each transaction on Steam). On a $70 game, that's $12.60 extra in their pocket for each sale. This is for all games, even if they're not exclusive to Epic.
Epic also has a program where if you launch your game exclusively on Epic then you keep 100% of the sales transactions for the first six months (after which time, your exclusivity contract ends). That would give them an extra $21 per sale vs launching on Steam. Honestly, the smart business move is to launch this way on Epic first, then on Steam when the exclusivity deal runs dry. You'll even get a certain cross section of people who will double-dip.
Square likes money, and I'm sure their pencil pushers probably don't even know the difference between Epic and Steam. The last few big Final Fantasy games on PC (Remake and Strangers of Paradise) both launched as EGS exclusives for this reason.
There was some sort of "insider leak" on Resetera a few weeks back, someone claiming to be an insider saying it wouldn't be exclusive - but I think they were probably full of shit. I guess time will tell.