You are looking at some expensive stuff. I would start out with some simpler, straight forward printers.
Just my suggestions.
1. QIDI X-one. Smaller build volume single extruder but heated bed and bullet proof tough printer. does a nice job on PLA and ABS. Inexpensive.
2. QIDI Tech-1 or Flashforge Creator Pro. Dual extrusion, heated bed and enclosed. Again straight forward reliable machines. All of these can be converted to all metal hotends to do the more exotic filaments.
3. The Prusa MK2s is a great machine and could be a good teaching tool building the kit. Set up and cared for correctly it is a workhorse that is capable of great prints.
Larger volume you may look at the Folgertech FT-5. Inexpensive kit but not for the novice. I am just starting a build on one now.
I would go for cost effective printers with parts that are readily available and reasonably priced. No real restrictions on proprietary filaments etc. and have setups for the main stream slicers.