Calculate future dates and promotions based on current information on attendance sheet

Greetings, I run a kids boot camp program and am having trouble manually tracking upcoming events. I'm trying to calculate three separate functions:
1. identification of a future date based on current date and number of classes purchased (when current registration expires)
2. calculation of total classes attended ( I think I've figured this out with a formula)
3. Identification of the next promotion date based on how many classes they've already attended and how many classes they have to reach the next rank.

I've attached a sample of what I've been tracking manually. Any help would be greatly appreciated.

Regards,
Alex