The green one is definately a Mustang.
Got one and a half here.
The matt black one looks like a slightly newer mustang or it could be a high arch, victa or sunbeam with newer wheels which is probably more likely given the carb on it. The power torque muffler clip is even more strange.
Looking at a picture of my old mustang the wheels are about the only difference, well other than the power torque motor.
The sunbeam i have here has the older wheels like the high arch did. I put the high arch lid on the sunbeam, i sat the original broken one on top for the pic. The ZIP start you have on the blue painted one, which one was that off, looks the same as the one i have here off the sunbeam.
None of the mowers i have here are like that blue one at the front.
I have a VC sports, it looks to be the same base as the green mustang but orange. Had a mkIII series 70 on it.
The one with the fancy yellow wheel centres, the top looks older than the rest of it. The ZIP start built in instead of in under the cover.
Interesting stuff, would be a rare thing to get a mower that has not been messed with.
Cheers, Bob.