That's quite a long message but I'll try my best to respond to all your questions, also a reminder that my field isn't astro so there may be answers I do not know.
You asked if by negative energy/mass i was referring to antimatter, and unlike the confusing naming would suggest, they actually have nothing to do with one another, antimatter has positive mass and energy and exists, negative mass/energy is purely theoretical
I dont know what you mean with the black hole needing to spin, all natural black holes spin as far as I know, I also don't know what you mean by doughnut shape, if you're referring to the singularity and the effects of the ergosphere on it then I can inform you I have absolutely no clue what happens there and no one really does.
You also mentioned that Tucker might have moved to a universe with a different handedness/parity, that was a creative idea i haven't heard before, took me some time to properly think about it, it's probably not what happened because a basic change of parity would fck up lots of stuff in noticeable ways.
as for all your worm hole related questions, I have no clue, I know they're natural solutions for einstien's field equations and unstable so would need negative mass/energy to work but no more than that.
You also asked if a black hole generator would be easier and/or safer than say, a Dyson sphere or swarm, to that i say they're both sci-fi, at the end of the day they're both just fictional ideas, so both are not practical at all
It's nice to know that people are that interested in physics, and you know a lot about this subject, but I wouldn't fret about finding an exact physical phenomenon for the Mæron, imo its nicer to theorize broadly, most sci-fi doesn't exactly follow the theory anyway, and to be honest I like it better that way