Sorry if this has been answered already but are there any plans to add more characters at/post launch aside from Eliza?
I know lore-wise it wouldn't make much sense for Beo to be there yet
I seem to recall they said this game would jump around and show storylines from all over the Skullgirls timeline, so it's not specifically restricted to Prequels. Could be wrong on that though!
If it does stick to prequels, then Double and Beo are both fair game. Double is hundreds/thousands of years old and Beo was a wrestler 14 years ago until dropping out of the ring. He was still around.
(There's actually a bug already where you can get Beo's character coin to display. Probably just because he's alphabetically the first character)
Fukua and Robo Fortune are both viable as non-canon and could just be stuck in for whatever reason. Fire Emblem Heroes has clear canon / non-canon story sections, so it's not unheard of.
They could even use characters like Isaac to bring characters forward and backwards in time if they want... Skullgirls as a universe is pretty open ended so there's any number of reasons to make characters playable.
Regardless of the reason, it is very expensive to produce Skullgirls characters. You can bet your butt they're going to use all the existing animations they have! Everyone who is playable in Skullgirls on consoles is basically guaranteed to show up on mobile.