Hey there! TBH most rubber feet fall off all stands at some point, it's just something to always talk about with kids and keep a look out for. T bolts too, although that's a bit more rare for me. Only happens when they loosen too much when leaving performance areas and don't retighten. Def have that convo with them

As far as the legs sliding, I have not had that issue, although I do not use Randal may anymore because I had other issues with the air frame and legs (slipping and falling even when tightened well)

At this moment in time, Pearl is the best all around. Dynasty great too but the legs don't allow for much adjustments in the stands- good at everything else. Mapex is the same way. Yamaha uses Randal May too unfortunately. Ludwig I am unsure of hardware wise. That's about the only options in the market as far as I am aware!

Good luck to you and your students!