I will be putting 20% down and am looking to go with Conventional financing.  

Note that I have a good credit score but I do have a foreclosure on my record from 2015 which prevents me from going the conventional mortgage route.For example a house I am looking at sells for $110K and the rent is $1095.

For a conventional loan 15% down is required for single family non-owner occupied and 25% for a 2-4 unit  non owner occupied.

Often times it'll be a conventional loan with an occupancy requirement.

We bought this home as a foreclosure with a 30 year conventional investment loan.

We financed this deal on a 30-year fixed conventional mortgage with 20% down.

We financed this deal on a 30-year fixed conventional mortgage with 20% down.

If you're looking specifically for a 4-plex, close to the base, there's even less inventory. 

For a fixed rate 30 year mortgage, you could rate and term the first 7 and then purchase 3 of the 5 with conventional financing. 

If you plan on moving into the property, you might be able to do the owner occupy 3.5% down FHA loan, or if you aren't planning on moving in, most of the times it is 25% down with a conventional loan if you go that route.