Hi Davina
Based on a number of holidays with JY ;-
Question 1 - There is always a reasonable gap between arriving back at the hotel and dinner, as everyone (or most people) will want to have a shower etc. I've never been on an organised holiday (with JY or anyone else) that is so short on time, that there isn't spare time in the schedule.
Question 2 - Often there are shops near the hotel, if not in the hotel itself, if this isn't the case I'm sure the Tour manager will make some time. You won't be the only one who want to do this.
Question 3 - Again there has always been time made to do this, usually there is some free time allocated at any particular place you visit.
Question 4 - I've never know anyone refuse to take this sort of photo for me. If someone did refuse I would just ask someone else in the group.
I'm 100% sure that none of your concerns will turn out to be problems.
Enjoy the holiday.
Stuart