I don't know how hot is too hot but around where I am, 82°F is a refreshingly cool day. It's over 90 here every day for months during summer and the holiday cacti love it -as long as they're not being eaten. 50% humidity would be noticeably low, 60% is noticeably low this time of year.
I don't think humidity or lack of it is a big deal. Really high humidity causes a lot of aerial roots to grow, which are interesting but later they shrivel up and look like brown strings which aren't an attractive addition, to my eye. If not cut off, they'll fall on the floor.
To propagate, I have a better success rate laying segments horizontally on the surface vs. trying to stick them straight up. Sometimes the straight-up ones rot instead of taking root, but there is a longer wait when starting sideways.
Various pros/cons to weigh against personal preference, amount of material available, curiosity, etc...
