Not likely. Didn't the devs say that they didn't want to make a fem protag from the start?
Something about Joker's "magician" motif not being applicable to women.
There's still some consternation surrounding that, mostly stemming from a datamined string in Smash Bros. Ultimate that references a potential alternate outfit for Joker that itself makes mention of a "Jane" - Joker's referred to in-code as "Jack" - and a ponytail. It's flimsy, and certainly doesn't confirm anything, but if true and there is a female alternate Joker planned, it'd be a first for it to be a completely different character and not just a gender-swapped counterpart a la Wii Fit Trainer, Villager, Robin, or Corin.
If we go further out on this branch and assume the Smash leak to be true as well as the Persona team's stated intentions then it could mean P5R is still getting a female MC, only she's going to be a significantly different character from Joker. That would play into the speculation that in-universe Joker inadvertently replaced the intended protagonist and this new FeMC is who he unwittingly usurped.
That's a hell of a leap in logic, sure, but wild and rampant speculation is half the fun with these sorts of things.
At this point, there isn't enough information to gague who she is. We don't have a name (or if she'll even have an official name) or her role in the story. All we have is her looks and what we can gleam from that. She is a first year student at Shujin. And her Japanese nickname is Poniko, from her ponytail.
Full fanfiction wish here, but considering she says in the trailer she doesn't approve of the Phantom Theives' method and think it is better that change comes from the individual, I think it would be better if she is the FeMC, she grouped up with Gorou became a parallel route to Amamiya where she tries to redeem the people without having to brainwash them.
Have the route show the actual potential negative consequences for brainwashing people the original P5 discussed but never explored and therefore turns Amamiya into an actual antagonist.
The route can lighten Gorou's sins, make all the conflicts post-Kamoshida or maybe Madarame Amamiya's own fault, so Gorou still would be guilty for the crimes that happened before the story of the original P5 and you'd still get a boss fight with him, but he would be redeemable and be a largely permanent party member to FeMC. This way we won't have to rush through Gorou's character arc like in the original P5.
Amamiya, as the antagonist, can stick with his party of Ryuuji, Ann and Morgana while Yuusuke, Makoto, Futaba and Haru would be recruitable for the FeMC instead. Maybe, Hifumi would also be a new party member for the FeMC, as per her original character concept.
But alas I presume this would be like creating a new game entirely so I highly doubt it will happen, but it would be better than just setting her as another "I was doubtful of the Phantom Thieves method before but now that I am in a Palace I will totally believe everything you say from here on out!" character.
Full fanfiction wish here, but considering she says in the trailer she doesn't approve of the Phantom Theives' method and think it is better that change comes from the individual, I think it would be better if she is the FeMC, she grouped up with Gorou became a parallel route to Amamiya where she tries to redeem the people without having to brainwash them.
Have the route show the actual potential negative consequences for brainwashing people the original P5 discussed but never explored and therefore turns Amamiya into an actual antagonist.
The route can lighten Gorou's sins, make all the conflicts post-Kamoshida or maybe Madarame Amamiya's own fault, so Gorou still would be guilty for the crimes that happened before the story of the original P5 and you'd still get a boss fight with him, but he would be redeemable and be a largely permanent party member to FeMC. This way we won't have to rush through Gorou's character arc like in the original P5.
Amamiya, as the antagonist, can stick with his party of Ryuuji, Ann and Morgana while Yuusuke, Makoto, Futaba and Haru would be recruitable for the FeMC instead. Maybe, Hifumi would also be a new party member for the FeMC, as per her original character concept.
But alas I presume this would be like creating a new game entirely so I highly doubt it will happen, but it would be better than just setting her as another "I was doubtful of the Phantom Thieves method before but now that I am in a Palace I will totally believe everything you say from here on out!" character.