I'm not actually asking a question, because this is the answer: You cannot set up a charity to accept Venmo if the only mobile phone number you have is already associated with a personal Venmo account. Why? Because Venmo has not figured out how to allow concurrent accounts on a single mobile number. Sigh.
I confirmed this with a third-party, nonprofit fundraising-focused website; Venmo does not specify this anywhere, despite it being a fairly straightforward and logical question to ask. Oh well. No Venmo for our org.
