Should we import fundraisers first?

Absolutely.  In particular if you are looking to Soft Credit a fundraiser, then we recommend importing the fundraisers and selecting the "Contact Only Load" on the first step.

The Contact Only Load checkbox will import the contact and de-duplicate the contact with existing contact or create a new contact if they do not already exist.  This will NOT create any related opportunities though.

Loading the contact first will ensure the contact can be found and when using the Nonprofit Success Pack, can be soft credited for with the subsequent uploads.