before bothering with the spark, does the starter even turn the engine?
I assume not since you replaced all the starter parts.
Check the clutch sensor, kickstand sensor, neutral sensor. Personally I would likely just jump out the starter relay and see if the starter spins. If it doesn't, you have an issue with the battery or starter, or the wires between them (not many wires to check).
If it spins, go for spark/plugs. Might need a carb cleaning now, not sure how long it's sat. Disconnect the regulator/stator and test without it connected, could be a fault there.