I think it will be Gen Fu, he's a pure DOA cast member, Momiji I don't think will have priority over him, especially without Rachel alongside her
Free Step Dodge
KasumiLover
Onryoki
Gen fu
Force_of_Nature
Right now, likely neither. They'll be DLC later however.
deathofaninja
I think Genfu should always be available from the start. Momiji will not come without Rachel... more use for more heavies so I would give it to Rachel over both of them.
ChaolanLegacy
Maybe Momiji. Gen-Fu in DOA5 passes down his (I think) fighting style to Eliot so there's almost no reason for him to come back as a story-relevant character, while Momiji wasn't present story-wise yet, so there's more chance for her to make it into the base roster in my opinion. If not, then its probable that they'll be dlc later down the line.
deathofaninja
It's funny that they advertise the game as an "esport title" but then when they ask how they pick characters they say "relevance to story." Genfu still has more purpose to the story than Momiji, and more players use Genfu offline -- so yeah. He should be in before Momiji.