Financing for rehab of a MF 6 unit? Lease out to flip?

[Carson Wilcox]

I am looking at a 6 unit.  vacant.  2 3 unit buildings.  

Purchase will be like $580k, probably $20k per unit average rehab MAX... Originally I was thinking to BRRR it, still might... But I am now thinking flip. after driving the neighborhood... not too into it...

What are my options for flip financing...?  Just Hard money?

Also... realtor/BP new friend says it will sell better if it is leased up with tenants before selling.  Thoughts?  To me, this seems a pig in a poke... spend $10k in holding costs renting it out, and all the $ involved... to MAYBE get a better price...?  OR will the prospective buyer want to see it rented for x$ per month in order to justify price?  Love to hear some experiences...