I spent a lot of time with Jax last night. He has a really easy TOD infinite w his ground pound (until it inevitably gets nerfed). You can also call him in after a second db3,1 to extend combos even further.
I don't think he's the best for OM but the infinite is easy and fun to do. It's basically;
launcher, j212, air dash, j12 1+3, ground pound, dash forward into viltrumite stance, and repeat. I'll post a video later today.
Since it is meterless you can add in as many air dashes as you'd like and it will eventually lead to death. Super easy to execute once you get the timing down, but seeing as omni man isn't the only character thay gets an infinite from jax its not very special either.
Besides the infinite, I don't really see a lot of utility w Jax and am still leaning towards Kung Lao being the best/safest option for him, but it's only day 2 so there's a lot to be explored! Imma try out Goro and Kano today