Prehung doors come with the frames and hinges as one piece. Generally have the holes drilled for the openers. Slab doors are simply the door, no hinges/hardware location holes. Installing prehung doors means you remove all of the old door and frame. You then locate the new door/frame unit in place, plumb and level the frame members, and attach to the wall studs using shims(for plumb) and nails/screws. This can be done with a level, hammer/nails or screws/power screwdriver(drill/etc.). You would need a flat pry bar and hammer/screwdriver to remove the old frame. A reciprocating saw makes that job faster by cutting the old fasteners. Installing a slab means removing the old door, using it to cut the new slab to fit. cutting hinge mortises and opener holes, installing the hinges/hardware, and hanging the slab in the old frame. Replacing a slab means the door is seldom plumb or square and there is a fair amount of difficulty involved in machining the mortises and cutting the opener holes. You need two different sizes of hole saws and hammer and chisel as minimum tools. Professional tools include hinge location jigs and routers for the mortises along with the hole saws. Hinges in prehung doors are generally basic brass colored, so matching hinges to opener hardware would require new replacement hinges. I do not remember ever replacing hinges to match opener hardware. There are lots of videos showing both processes on YouTube.

Yes.

Interior trim or exterior trim? It may also help to post drawings of the design and what the trim is like. WARNING: Posting your entire floor plan opens you up to facts you may not want to know, but should. Be prepared for suggestions that will make for a better design. Keep a thick skin, open mind, sense of humor, and a glass of wine within arms reach. You may not enjoy it, but everyone else will and you will be better off in the long run if you heed well the advice.

IMO I would do a different style from the same makers like maybe one bar to line up with one bar form the patio door but really patio doors do not need to amtch inter doors at all. Do you want all glass doors and where do those doors lead . I am wondering why a door there at all so maybe share where that doorway leads Just for my own info what is that ceiling material?