Lilly is lovely, and if you're anywhere near as awesome, you'll fit right in (which you do already because Sherlock is amazing). I'm Anne. I said hi in the chat, but this might be a bit easier to keep up with since the chat sometimes gets zany.
Also, I love how you have her showing up already because I love for chaos.
Anyway, here's my list. As always, lemme know if you have anyone that strikes your fancy for plot:
Carol Danvers (MCU): Captain Marvel herself. Carol comes just before Endgame, and has settled into town running the local bar with one of the Peter Parkers (the oldest one). She's sarcastic, bull-headed, and flirtatious. Sort of a 15 year old boy inside. She's also a little bit bossy and hates not having control. Being stuck in Starklandia has been hard on her.
Miles Morales (Spider-Verse): Miles is your typical teenager, except for the fact he's Spider-Man. He comes in shortly after the film, literally having been on a walk home from school. Currently, he's living with the older Peter Parker (who he knows from the movie) and killing time by working at COFFEE and practicing street art. He's awkward but friendly. He'd be terrified of Irene.
The Doctor (DW): The Thirteenth Doctor is friendly and outgoing, and has basically been spending her time trying to do what she can to figure out the mystery of this place and help people adjust to living here. That or helping Rose get out of trouble. Or into trouble. It depends on the day.
Harley Quinn (DCEU): Harley will love Irene once she figures out what she actually is. Well, she might also hate her considering their similar natures. Right now, Harley's been causing little bits of trouble around town here and there, but mostly biding her time as she watches and plots. The worst she's done is kill a few people on the other side of the doors and break some windows around town (oops).
Obi-Wan Kenobi (SW): Ben is stand-offish for now. He's been through the doors only once, but since meeting Leia he's been trying to figure out how to get out of here and back to their own universe and times. He comes from shortly after he watched his protege burn after a battle, so he's a bit emotionally damaged. He'd be suspicious of Irene, for sure (but still friendly).