Adding new players to campaign

Good mornings spooky going folk, I have a player who is just about to have a kid and might need to step back from the campaign due to fatherhood responsibilities. So i'm looking to add two more people to my campaign, does anyone have suggestions on how to do this, making it seem natural?And not just plop, two new players into Barovia. Both people who are interested in joining are really good at role play and seasoned ttrpg people. So i'm not sure if I should limit race or class specifics. I don't want to tell my players.You can't play this or that because xyz. But should I limit them on anything when creating a new character, besides avoiding similar characters that are already in the campaign.

Thanks again always, The forever DM

Like they should be people from barovia? We just got to the valaki vastani camp.