Gary - the lifters are suited - but not sure there's room 'to the sides' to get it in and jacked up....
as I drew through the tilting plate it just got more and more complicated due x,y and z, so I dumped the idea.
actually, the lever solution you linked is the most elegant - the glitch is where to get a hold on the chassis.
the photo shows a possibility - appears to be a vertical U or box strut which seems tot be part of the motor mounting - see the circle:
here's a lever solution - sorta' to scale assuming a 14" wheel and 3" casters.
looks like all hard surfaces, so a 2" caster would likely work fine - especially if it's clip on, move the back end, clip off, drive in/out of the apartment.
the lever is simple, needs access only from the rear, and should be reasonable light weight.
I would make it a rectangular box, the inner cross piece for stability and the outer as a treadle; two pieces, a roughly 2x4 with dowel to go in a hole in the treadle and a high friction notch to fit the yellow bar and hold the treadle down.
the nose pieces need a notch and a bolt head / something to ensure they don't slip off the vertical strut.