thanks for continuing to follow back up, here. Have you made sure your valves are adjusted properly? That can be a cause of a 'no start'. It's a relatively easy procedure, no new parts needed, just a feeler gauge and sockets and a wrench. Lots of youtube vids to walk you through it.
If you know you have fuel, spark and compression...hoping the valves are out of adjustment and that will fix you up.
Regarding a carb 'rebuild'...it's in reality a carb clean. You usually don't have to replace anything in the carb, just have to make sure everything is squeaky clean and working correctly. The use of starter fluid not being able to start the scoot makes me think it is not carb related, though.