Jeff these are my favorite machine, lots of questions there just go one step at a time.
1 tired full crank, if it runs ok with no bottom end noise, a hone and a new set of rings shoul;d freshen it up.
2 The used a boss that was also the pulley, as long as yours works it should be fine
3 The snorkel is obviously from probably a Powertorque mower the snorkels from a utility are shorter and have instead of the lokg rubber tube at the bottom a little short 45 degree elbow fits straight onto the carby and as you thought the carby is fitted upside down with the primer cap facing forward and turned 180 degrees to the way it is on a PT.
4 Depends on the 24 Base, some were designed to take the Briggs motors so if you have that sort of base a PT will fit, if not it is a lot of work to fit one. I did one a few weeks back, should have fitted a PT to the one I was building but decided I wanted to use up some of the full cranks I had here, turned into a big job
5The tension adjuster is a ring around the crank above the pullet with a bit of threaded rod out through the back so tou can tighten it up before you tighten the base bolts up.
6 Depends on how bad the housing has torn where the front axle goes through the body. I have made up delrin bushes to fill the gap and a "J" type bolt to pull the axle up tight . Victa wheels were standard but I use whatever good wheels I have here.
Hope this helps
