Do you have any suggestions on what should I do if my vision is obstructed after stopping behind the crosswalk?
You have to move up until you can clearly see your way, remember to stop again if it's necessary
I am aiming for a MJ license because I'm into motorcyles, does the 50 hours of supervised practice applies to MJ as well?
Pretty much the same. You must have a minimum of 50 hours of supervised pratice driving, and that includes at least 15 hours after sunset. So driving 15 hours at night is important.