Well it looks like, who you ended up with in the original game doesnt matter. Which kinda sucks, but to be fair: the premise of the original is that she inevitably made a harem.
So theoretically, Val could refer to all of them as "mom" and there be a main "Mom" who is the one you ended up with. Leaving the rest to simply be refered to as Mom.
Why would there even be a main "Mom"? I haven't played this one yet so maybe something contradicts this, but you were presumably adopted into a family of poly lesbians. I suppose two parents might have had to be picked for birth-certificate purposes, but beyond that they'd all equally be your mother. If one of them actually is your biomom, it's probably Lawrence.
By main "mom" I'm refering to the person you end up with if you dont got down the harem route. I could be misremembering, but if you chose like 1 person, dont you adopt V with whoever you chose in the end? In my playthrough of AR1, I remained faithful to the first love (cant remember her name for the life of me).
But in 2 its revealed that you ended up with the Fujikawa girl.
It will also be more complex to take into account all the AR1 possible endings. There are 12 endings! More work, and more risk of bug.
HanakoXVN stat that there isn't ONE cannon ending, but any ending with at least one of the Fujikawa sisters leads to AR2.
Valerie is adopted (like Spoon, but he was adopted first! :-)). One of her legal mom is Violet. The other seems to be the Fujikawa sisters Violet ended with in AR1.
Valerie call all the other girls (Violet may have ended with too) as her moms (she said she may have too many moms :-)), but Violet and the Fujikawa girl are her legal moms.
The only question remaining is what with the Legend Ending where Violet ended with the two Fujikawa sisters. I have the feeling the second legal mom will be Rikako, but it's just my 2 cents.
Anyway, HanakoXVN has explain that the exact number of Valerie moms will never be specified in AR2. And I think the only one Valerie will have contact (and we may see) will be Violet.
Thus, any ending from AR1 with one of the Fujikawa sisters will work.
