The first step is to get pre-approved for a loan to determine your max budget. 

I ALWAYS have a loan on my primary because they are the easiest loans to get and have the least amount of expense involved.

Just got denied lending from a supposed HM lender due to the source of the down payment coming from a personal loan.

There is no way to know what the lending landscape and his options will be in five years from now - that type of loan could still be available or there could be some differences - including nuance with the specific property, location, etc

@Gilberto Ramirez III a fix and flip loan (12 month interest only loan) to purchase and rehab the property.

If you qualify for a solo 401k (self employed with no w2 employees other than a spouse) you can take what's called a participant loan. 

We've got some capital, but I've heard of investment loans that require zero % down as long as we can show that the property will be able to rent.

I house hack but the loan is still considered my primary residence so I guess I wasn’t considering it as an investment property that contributes to my NW.

Are there any loan options out there I am missing to keep out of pockets costs under 100k?

Also - get a free  full loan pre approval in place for whatever  hypotehtical scenario you are considering  to make sure you have  finnacing lined up