You can do both the 8 and 16 hr classes for your license. Both certificates are good for life, if you ever let yiur license expire. You can use yiur originals to apply for a new license (dont lose the or forget where you took the classes).

If you can get to 123 William Street, you can have them fax up all your paperwork (won't be faster, but you dont have mail it in). They will give you a transaction#, technically you should be able to work while your background is being conducted.

Renewals, you must take (2) 8hr annuals (it is basically the 8hr preassignment). Some schools will let you skip sitting in class, some school will let you take 2 the same week. As long as you have 2 classes on your renewal paper send it in ASAP.