Is there a place where I can map fields that I want imported from SFDC into Clay?
It’s currently importing only certain fields and I’m not sure how it’s determining which (and I want to add some).
Yep, your assessment would be correct. It takes the visible fields from the selected list. If you activate other fields in that view and run the import again, it should update... you can also run a SFDC Lookup on the existing import to get those updates.