Seriously doubt that. For the same reasons before. There are 4 and the bike was running.
If you are sure you're getting fuel.
And you don't have a mouse nest plugging your airbox.
It's got to have something to do with the timing of the spark.
Personally, I'd go back to double checking anything that might affect that.

 

Seriously, it'd take like 10 minutes to try jumping it off a car. Disconnect the motorcycle battery and hook the jumper cables to the car. There's a reason why mechanics always start with the easy stuff first

Confirming timing is a solid suggestion. Wonder if the coil leads got swapped or something

Also, have you confirmed throttle cable and choke cable operation?

Plugs don't really foul very often on modern engines. Especially 4-strokes. They would have had a visual when you checked spark, no?