I can’t speak entirely for your 4runner but my 2016 with 65k has thrown those three lights at me a few occasions now. The first time, I lost traction on ice and it just turned on, I had to clear it days later then spoke to my friend who used to wrench for toyota for 30 years, he told me it is just a modern sensitive toyota electronics thing and that it was not a problem. Then it happened again two more times, one of them being two days ago....both after I did some work/mods on the 4R in my driveway but the codes cleared themselves by next morning. Hope this gives you some sort of relief but if doesn’t clear itself get a mechanics opinion.
As for the squeal coming to a stop in reverse, is it happening when the cars cold? If you search online, many people have had their concerns but apparently it’s pretty common on Toyota’s and/or most vehicles. My toyota buddy told me its just the brakes adjusting fast from reverse. This also happens in mine and while it used to concern me, I’ve learned to ignore it.
Hope any of this info helps and good luck.
