the benefits of running reports on estimates?

If a customer is tax-exempt, you can change in the invoice screen?

1. If you convert an estimate to an invoice, can you change the criteria (as in prices or items)?
2. You have to set the state comptroller as a vendor? (For Sales Tax)
3. You can just pay sales tax through the vendor system, like a normal invoice or bill?
4. If you don’t close the books yourself, how often does Quickbooks do it?
5. If you receive multiple checks at once, but record them into the same account at the same time, how do you deposit them?
6. You have a Beanie Babies distribution company.  What could be a COGS (cost of goods sold)?
7.