Size factor of capacitors now and then?
So technically, I could replace the beefy transistor by one of same value that I gather from broken fluorescent/led lamps?


In principle, yes. But the small motor in the picture is only rated for 6 watts of power, and you need to ajust the size of the cap depending on how much your motor needs. Note that the cap is also rated for 400 Volts (X or X2 cap).