It's alright, but if you really want it to be Injustice, one could add Injustice-like mechanics to the game, which are probably impossible in MUGEN. Making it JLTF2 is fine with me though, and maybe a better move than making it an Injustice game.
Then maybe a new screen pack and boss too...anti monitor...your juggernaut from miw might work as a base
Finished up this for MIW:https://s5.postimg.org/f3803vwg7/OHT1939.png
Also, there's a few more characters I want to do sprites of but can't find bases for. These include Peggy Carter, Rawhide Kid, Man-Thing, Slapstick, and NFL Superpro. I think someone from Sunset Riders might work for Rawhide Kid, but the base I wanted for NFL Superpro hasn't been ripped yet.
On the other hand, I think Spider-Ham and Kraglin will be next. Maybe 2 to 4 more with them?