FWIW I’d go with seeing if you can get comfortable around him first, as suggested here. I definitely agree that you have to be ready before going on this trip, and hanging out with the dude to get to know him would be a big part of that. Because the truth is, the two of you likely have a some stuff in common and you’d probably get along really well under other circumstances.
If you’re not mad at her anymore, maybe it might help to view him through the lens of someone who makes her happy; there’s also an opportunity here to make a good friend who you can trust to take good care of her and your son if something happens to you. If you do decide to meet up with him, you might even ask her about some things she thinks you might like about him so you have some conversation starters. And, it’s clear that there’s good will on the other side to try and mend fences for the sake of the kid, which speaks well to both his character and that of your ex-wife. They could have just said no and never mentioned it to you, or worse they could have been scheming to cut you out of your son’s life. A holiday invitation kinda says a lot about how they view you, when you think of it like that.
However you decide bud I hope you manage okay through all this, and I do hope you can find a way to be friendly with him. It’s incredibly strong of you to even be considering putting yourself out there like that. As evidenced by most of the comments here, that would not be a common reaction. Good luck!
Not too far, or its possible right now depending on jow you want to define “animated”. I feel like there uses to be really low-budget cartoons on air which were really just still frames with some shake added, couple soumd effects, and voice acting. A lot like SolidJJ on YouTube now. Those wouldn’t even be too hard to do, if the AI were just one tool in the set - could probably crank out a few a week, anyway.
If you’re looking for twenty minutes of animation that doesn’t shift around like a fever dream while you’re watching it, maybe six to eighteen months. I do think human voice actors would be required, but you could do the music with Suno.