HELOC or FHA on 4-plex for initial investment?

[Dr. Jordan E Smith]

Hey guys! 

Forgive the newsiness, but I would love your thoughts on taking out a home equity line of credit on a primary residence in order to cover downpayment/closing/rehab costs on a quadruplex. This would be my husband's and my first investment property. We do not currently have a mortgage, so we are also considering the house-hacking option, despite it not being super ideal for our family. 

What would you do if you had equity available, no mortgage (so FHA loan available), and were just starting out ?

House-hack quadruplex or purchase with HELOC at higher downpayment and rent out all units?

Looking for any experience or opinions, thanks!