You may have trouble renting without getting your dad in on the transaction; maybe they will just take a check when they drop it off and not ask any questions.
Out of that list I would say the John Deere sounds like the best digger.
As far as I know, any skid steer is available with a backup alarm but it is up to the individual dealership to order that option on their rental fleet machines, and then maintain the thing in working order. None of mine have had that feature and although I have hit a few stationary objects, have so far not run over any people or pets.
I think you will really enjoy running these machines and maybe this will be the start of something big for you. However it works out, great initiative!
P.S. The Case Construction Equipment website has the most complete comparision pages I've seen on the web. I think it's www.casece.com
and just kind find your way from there. Should be able to compare widths, horsepower, and about 30 other specs on a LOT of different manufacturer's machines.