Hello again, @NewUser2021-.

Allow me to share some details about the features available for you to use in QuickBooks Online.

I can see the importance of tracking the inventory to the next level. However, moving inventory to a different location is unavailable in QuickBooks Online. I'd recommend sending a feedback to our Product Developer department to consider this on our future enhancements. Here's where you can send feedback in QuickBooks Online:

Regarding on your second and third questions, you can import the customers and the vendor's information via Excel or .CSV file. For the basic inventory and sales tracking information your Lightspeed Accounting account will get the data from QuickBooks to be mapped. Just click the Refresh Reference Data in your Lightspeed account. I've added a screenshot where you can see this option once your QuickBooks account is connected:

This would also update the data you have in your Lightspeed account. Take note that this option is for manual update. The auto update will happen once a day, every night. I've added an article from lightspeed for more details: Mapping your Data. 

You're always welcome to comment below if you have follow up questions. I'd be happy to answer them. Take care always!