You're definitely walking a fine line when choosing to do it.

Fannie/Freddie have MHC products that would be a better fit here.

Run, don't walk and find a "happy place" to invest.

Dont let them walk all over you but be firm and fair.

By that I mean, if you were, and you’re confident on your analysis, then either the property fits your criteria (thus further due diligence) or it doesn’t (and you move on). 

And...most of us fit into this group, when we first began as well.So here is my tip for those who need, want it, and glad they have it. ( I wish I could have this posted some place where I wouldn't have to hunt and find it every time someone asks this questions on here, but perhaps the owners of this site might tag it, we will see)So...here it is.THIS IS THE PLAN1.Location, Location, Location .2.

New walk in shower.  

Both units also need brand new septic systems, which the seller will replace.My question is...should I wait the few months for the seller to take care of all of these issues and make sure that it is done right before I purchase, or should I offer him a low-ball cash offer to walk away and then get a HELOC on the property to purchase my next investment.

I buy in south Dallas TX and it fits the formula perfect. 

When you walk into a phone call, meeting etc. with this in mind it sorta makes the large issue silly, I often start meetings this way...to pull everyone out of the legal/expert arena and into....oh we are actually all trying to survive and syndicate a solution together.