Thanks for your replies!
curious aardvark - I was planning on using two stepper motors for the z axis, since it is simpler to have it lower and raise on two shafts instead of one.
I don't know anything about the different types of filament, so I will be reading up on that.
When using cold plate filament, do you still have to heat the surroundings like you suggested in an enclosure or something? If not, then I will definitely go with cold plate filaments! Haha

soofle616 - Link has been fixed. I'm not sure what a "bowden extruder" is. Is it just an extruder mounted elsewhere than on the platform itself? I will be raising the Z platform instead of lowering the bed between layers. I will aim to make it as light as possible! Sounds good with the engraving, too! Makes sense that milling requires sturdier and stronger parts, though, so I will stay with printing and engraving. Thanks!