Okay, another update...
I called my orthodontist's office this morning and said I needed to see someone, anyone, immediately. They made an appt for 4 hours later (1pm) with another orthodontist (he's actually the one who did my first consult, and apparently quite a TMJ expert, but he is retiring and isn't taking new patients. So before I was braced I got passed to a new ortho. Anyway, long story short he agreed to squeeze me between other appointments today).
So I explained my Tuesday appointment, and everything I've been dealing with since. He spent a lot of time asking jaw-pain related questions and checking out all the muscles in my face/jaw/neck/head noticing all the swelling and "nodules" that have formed in the last 2 days. I have a bad joint popping... the worst it's been in years.
He said 2 things happened on Tuesday:
1) They skipped a wire strength, so my new square wires are: a) my first square ones and b) one strength higher/stronger than he expected
2) My new wires go back to my back molars, my 7's, for the first time.
I knew about #2... I didn't know about #1b. He said the increased wire strength on it's own would have caused some jaw strain yet would have been manageable, but in combination with banding the 7's it appears to have thrown my jaw completely "outta whack". All the muscles in my jaws are tense/knotted and that's what he thinks caused my bite to go out of alignment, causing what appeared to be a slight open bite and my lisp.
He cut the top wire back to my 6's, and the bottom (which he believes to be the key offender) back to the 5's. Immediately the pain & pressure were reduced by about 1/3rd. I felt a huge sense of relief... like my jaw joints were released from a clamp. The rest of my teeth feel a bit better too... the wire was angled into my 7's putting strange pressure on nearby molars.
My gums and jaw joints are still extremely sore and he thinks it will take 24+ hours for the inflammation to clear up, the pain to reside, and the lisp to disappear.
This post is getting much too long, but I should add that this retired ortho is concerned about my ability to have a successful journey in braces without being able to take the wires back to the 7's.

That worries me. He also mentioned that he firmly believes I need structural jaw surgery while I have braces on in order to make any significant improvement to my quality of life with severe TMJ.
I have to meet with my ortho in a few days to discuss everything.