Hi Kallie

I can help with some of those.
CU means for commercial use. This means you can use the items in the kit to make commercial products [ so to sell] What it actually means depends on the individual designers TOU [Terms of Use] which you should always read. In the scarpbooking arena it generally means you can use the items to make things for kits you will sell and sometimes to make a small number of craft items]
You can't make them to make a product to then sell as CU. You will sometimes see CU4CU. This means you can make items you then sell for CU.
PU means for personal use. You can use the items in your personal scrapbooking or as in the TOU. You can't sell things made with them or make any money with them.
S4H means scrap for hire. this relates to people who have a business making scrapbook layouts for other people. So if you paid me to make a book for you that is scrap for hire. Some designers allow their prodcuts to be used for that purpose.

V3, V4, I have not heard and can only think of version 3 lol. Hopefully someone else can jump in there.

Just yell if you have any more questions as there is always someone here to help you out.