Good Afternoon Wade Mask,
Thanks for chiming in! You may need to import or create each unpaid invoice for those invoices. I encourage you to use my colleague's article to assist with that: Manage outstanding balances for customers and vendors in QuickBooks Online.
Regarding the sales tax questions, you would need to verify with your accountant to see the best move. If you don't have one, we offer a ProAdvisor program where you can connect with experts. Many even offer a free consultation. However, sales tax won't copy all transactions. Some taxes will copy as journal entries, especially when moving data from one program to the next. The article below goes into more detail about this.
If you have any other questions, just let us know! We will do our best to address them. See you later!