Hmmmm.......some of the things on those lists I would not consider necessary, but, on the other hand, there are some things I would add. You should also check to see whether or not your jurisdiction (state/province) has requirements that you need to address.
One thing that hasn't made it on anyone's list is a drug inventory, both for in-house use and dispensing. And don't forget an inventory of medical supplies (needles, syringes, fluid lines, bandage material, IV catheters, urinary catheters, feeding tubes, splints, etc.) Both of those are made up of small costs, but they add up.
Every clinic needs at least a small reference library, even if you are on-line.
I agree a digital radiograph machine isn't necessary, but if not you have to include a developing machine. Anesthesia monitors aren't necessary either, IMO, if you've got good staff, and tonopens aren't necessary either, IMO - Schiotz tonometers are fiddly and historic, but they do work
I think some supplies for staff morale are just as important, but also not necessary (coffee machine, staff fridge).