I'm gonna go ahead and speculate here, just from my general tech knowledge and how injustice/wwe immortals worked.
You need at least 2GB of RAM. A phone with 1GB or even 512MB will suffer. You might be able to get away with 1GB, but If you're running on a half gig RAM phone you're probably not going to be playing it. They're graphic intensive games and eat up RAM. MKX probably more so.
I'd also say you need at least a 1GHz CPU. Anything lower than that probably will not work, and 1GHz will still probably give you problems. I'd say the optimal performance is gonna be around 1.5GHz and up.
Aside from those factors everything else is probably moot. Having a dual/quad core processor will be helpful but not entirely necessary. Besides, if you're rocking higher CPU and RAM chances are you're probably gonna have at least a dual core processor.
Screen size could probably factor into compatibility too. I know hearthstone is incompatible with my phone because my screen isn't at least 6in -_-.
The final factor is of course your ROM or storage. I'd say a safe bet is to have around 3GB free in storage. The game itself will probably be close to, if not over 2GB.
So the recommended breakdown is:
(I'll also share my specs for reference)
2GB Ram
(2GB)
1.5GHz dual core processor
(2.26Ghz quad core)
Above average sized screen
(Mine is 5.2in)
3GB in storage
(I have 18GB available)
Also for reference, I'm using an LG G2.
