We offered $75k under asking and they accepted. 

Right now I am on the middle of a flip no more cash in hand to make an offer so my only option seems to be investors or a HELOC against my flip or my own house.

We made an offer (which was accepted) and ordered a home inspection.

You may need to call once a month for a year and most times you won't talk about real estate, you offer your help if they need anything.

If they would consider, what kind of leverage would they offer? 

I would buy from a brand that is offering 1.9% financing like Hyduai.

Keep in mind that these homes are sold "as-is," so a thorough inspection is crucial to identify any potential issues that could affect your renovation budget and timeline.Special Requirements:Freddie Mac has a "First Look Initiative," which gives owner-occupant buyers an exclusive opportunity to purchase homes before investors can submit offers.

A better approach is to network with other experienced passive investors and review the offering together. 

I am always a big fan of sailing downwind, you can take that in the context of what the market offers at any given point in time, or geographically - meaning the type of inventory Sheboygan County offers.

Again PMI offers the lower rate because its less risky and offers insurance to the bank.So when you sell your current home try and keep as much as possible and avoid an "All Cash" offer.