I've read both threads, and I feel for you, because missing out on adult time you had been looking forward to in the evenings sucks, particularly when it is being indulged by the other adult via card games and cartoons.
As the ND parent of ND children, one diagnosed with insomnia at age 6 (and who is now 10), some of the stuff you said reads to me like Alyssa may be neurodivergent. Meltdowns, not going to sleep (outside of the holiday time and routine change as well), the whole thing of needing to be first, and for things to be done a certain way. (also the sibling's thing with the colour of the plate).
ND type insomnia can not be cured by being firm. Trust me, I tried EVERYTHING. however, we still set rules and boundaries, and manage to at least get a few nights where the child just stays upstairs playing on whatever device or reading or having ridiculous ideas and executing them exploring.
We follow a gentle path-of-least-resistance type parenting approach designed to minimise autistic/adhd meltdowns or over stimulation, but we also teach our children about how to negotiate the rest of the world, and it seems like your friend may be struggling with how to do this.
Also, you can absolutely be neurodivergent and still an arsehole, so I'm not saying that you should let your friend her Alyssa off for all of that (I'd be particularly pissed off about the last day air cushion incident in your shoes, it sounds like your DD handled it excellently), but if your friendship does survive this, it may be worth asking your friend if she's ever considered that Alyssa may have ADHD or something.
Girls with adhd are often missed because they don't look like the squirmy, fidgety boys with it, and early diagnosis absolutely saves lives. Take it from someone who knows.