Lots of people seem to keep wanting to submit unit kits and some people are even leaving out art work completely while showing off full blown kits with mod details and what level they get what skills.

I'm sorry but the truth is that:

They only want your art work and a little unit lore/backstory, they do not want your full blown kits and they definitely are not interested in your units if they have no artwork attached.

Yes, feel free to throw in 3-5 skill suggestions, or an LB suggestion, as they will probably incorporate some or all of it, but don't submit an entire FFBE wikipedia page for your unit and expect the actual units they make to even resemble your fully detailed kits.
Definitely don't submit an artless/spriteless unit with only their kit and even expect to be entered as a contestant.

I do still encourage you to try because you never know but I'm telling you now to set your expectations accordingly. Hopefully they take as much of your kits as possible so I'd say you can try (might make for better units too) but you'd probably be better off sending the 3-5 skill and/or LB suggestion as they'd likely respond more positively to less constraints with your units (as would players voting for your units).

But you need artwork as they've made it clear this is more of an art competition than a full unit, kit included competition.