✧ + mara and/or petra heheheuehehe
Agh this one is hard because I don't think he'd ever actually agree to meet either of them in person. He's so certain* that Mara is Riven, that Petra is either a dupe or a second imposter, and deep in his heart I don't think there's anything or anyone he trusts to break him out of an Ahamkara illusion if he gets caught in one again. He still has moments fairly often when he thinks he's still delusional and everything around him is fake. He's not going to risk getting up close and personal with a potential Ahamkara.
(* Fun fact! The reason Uldren's so insistent on Mara being an Ahamkara is because it allows him to be mad at her. Of course he's angry at Riven; that feels safe. But if he admitted any possibility that she were actually Mara, he might have to also admit that he's angry at Mara too, and he won't let himself do that.)
Mara and/or Petra would probably have more luck trying to talk to Bea, TBH. But even there they're going to have trouble getting through. Bea wants absolutely nothing to do with Potential Ahamkara Issues, and though she's more open to the idea that they might be real, she and her timeline's Petra aren't close, while she actively dislikes Mara.
Honestly the main conversation Bea would want to have with either/both of them is "hey, could you please just block Uldren already?"
However, Uldren has been thinking of directly confronting Calypso / the entire dashboard with his accusation that Mara is an Ahamkara. So if that's somewhere you're interested in going, we could do that.