danielharris

The point about measuring to the underside of the lip rather than the countertop seems to be the one that decides whether an under-counter unit fits at all. Since the cabinets are older and not level, a digital level and a set of shims seem worth having before delivery, and the door arc should be checked against the nearest pull, not just the cabinet face. On the drawer versus standard door question, the slide hardware eating vertical space sounds like it matters more for leftovers than for drinks. I would also check whether the cabinet sides touch the unit, since sealed sides would leave warm air nowhere to go.

The overhang lip is the one that catches people out, so measure from the floor to the underside of the lip, not the countertop surface, and check the door arc against the nearest cabinet pull. Since your cabinets aren't level, get a cheap digital level and expect to shim the fridge feet. On ventilation, sealed cabinet sides matter more than the back; if the sides butt right up against the unit, warm air has nowhere to go. Drawer models do lose vertical space to the slides, so for leftovers a standard door may give you more usable height even if access is less convenient.