It comes down to whether or not Pope Francis will make it clear these people have excommunicated themselves.
Well, as a matter of fact, Pope Francis has done exactly that with regard to politicians who vote in favor of abortion in Argentina. I suspect Biden and Pelosi will be told to not present themselves because they will be refused if they do. If they ignore that advice, I believe Pope Francis will refuse them right in front of all the media vultures who probably helped King Barry come up with this deliberate challenge and insult.
You see, if they're not refused, there's a filing cabinet full of articles and commentary ready to go for slandering the Catholic Church over permitting them to violate Canon Law because they're public figures, but not ignoring "the little guy" who's violates Canon Law by being divorced or living with his boyfriend. If they're refused, that's the other filing cabinet full of articles and commentary ready to go slandering the Catholic Church for refusing them over their "political" views as if murdering infants has nothing whatsoever to do with morality.
Pope Francis knows that's how these people work and I suspect he'd rather have them using the second filing cabinet and spewing the lie that abortion is a political and not a moral issue.
I suspect you are engaging in wishful thinking. Nobody wants an "incident" at such a joyous occasion.
Nobody will be refused Communion.