Question 1: Is there a way to view the vlookup table as a data sheet view that you can edit?
Question 2: When editing an item from the vlookup table is there a way to save and go to next item displayed in vlookup table without saving and exiting the pop up and then clicking edit on the next item?
I don’t have a ready solution to your second questions, but it is possible to do with custom js, but maybe editing directly in the vLookup table might be easier.
It’s hard to tell without looking at it, but you can start by verifying that you have added the code to the correct form (NewForm, DispForm or EditForm). If that is OK you can hit F12 and select Console to see if there are any errors there (in red) that could give some hints about what could be wrong.
I’m not sure I understand. If both Child1 and Child2 are children of the same parent you cannot prefill a value in Child2 from Child1 – only from the parent list as set up in the “Prefill values in child” in the vLookup config.