Met my meta yesterday; things seemed to have gone well.
I was super nervous about the meetup. Hinge invited me to go swimming with them yesterday, and I decided to take him up on the offer. Ended up not swimming because of impending rain, but I did stay for more than an hour. Meta and I didn't actually talk to each other beyond the initial greeting and the goodbye at the end. She was in Mom mode--their kids were the ones swimming--but I didn't perceive any glares or ill thoughts. It was more that we were each having different conversations with Hinge in each other's presence.
All in all, it felt like a good first meeting given the circumstances.