Kinetic/Vespa/Hobbit ~ Drill one hole in the frame and use spacers to take up the slack.
Tomos ~ Sacrifice a Tomos frame and remove the motormount/swingarm then weld it back on the HS50. Use the tomos rear wheel and swingarm. Tomos forks will also fit with a little work or use K10 forks.
103 is a bit harder because of the frame angle. you would need to weld a mount on that lowers the motor/swingarm combo to get clearance and wheel base correct.
V1 is a straight chain line swap, but you need to make a swingarm or mod a swingarm to fit somehow.
So the easy peasy swap is Kinetic/Vespa/Hobbit. Tomos is probably the better one to use, and 103 or V1 will be the fastest.