The one thing an early VP pick would likely help Biden with is $$$, which he needs even more of now given the convention is a month later, COVID-19, etc..
Given their name ID, existing donor base, etc. gotta think Kamala and Warren near the top of the list as fundraisers.

Warren raised more than Kamala--$110 million to $39 million. But Kamala would likely be a better fit on the rich ppl fundraiser circuit if that's what Biden need given Warren's rhetoric during the campaign about wine caves and private fundraisers.