Power Query - Manual Entry and Multiple Users

I have a file with details of open purchase orders. PO numbers are in the rows and there are several columns with various PO details. It is linked via PQ to two other files. It is used by multiple buyers and I'd like to dumb it down as much as possible. I need to be able to do two things that I haven't figured out yet:

1. Each buyer is responsible for updating delivery ETAs on their open purchases. These are updated at different times for a each vendor throughout the week. In the shared file that we previously used, buyers had a sheet for each vendor and we used VLOOKUPS to pull data from these sheets. Obviously, that doesn't work with a PQ chart. Is there a solution to this that I'm not thinking of?

2. I need a column where buyers can manually add notes to each cell.