The main thing that makes me deeply suspicious of this 'leak' is that there is a new character, Nimbus, pegged as DLC. This is extremely unlikely to be true, as new characters are introduced in the base roster and story mode; it's very difficult to advertise characters that people aren't already aware of, and it would obviously sell far less than anyone else.
Unless, of course, Nimbus is some sort of code word for another (actual) character.
That said, with the exception of Havik and Reiko being absent, this is a very nice roster, and it'll be great to have Rain, Smoke and Noob (my MK9 mains) back; I found the MKX roster underwhelming, and very few of the characters really clicked for me.
It does seem a bit... well, obvious, though, in the sense that the roster seems like a load of fan favourites thrown together. Maybe it's legit, maybe it isn't, but Ermac being relegated to KP1 seems odd - though not impossible - and Pennywise and Myers seem very obvious choices as DLC - lots of people have mentioned them for a while now. In a sense, that makes me think it's less an actual leak, and more 'what have other people on internet forums been requesting.'