I don't know if you have a specific reason for using an IRA vs. self directed solo 401k - if you can go the 401k route (self employed) then you have some serious benefits such as much higher contribution limits, less reporting requirements, more investment options etc.

What is the annual loan limit?

I'm about to close on a fourplex with a hefty pest report, but only a limited amount that's structural. 

I think it would be wise for me to partner up with this small group because of my limited experience, knowledge, and funds.

You can refinance immediately with no seasoning using the current appraised value however you are limited to 75% (not 70% as alluded here) and the total new loan cant exceed your initial acquisition + closing costs.

@Russell Brazil and @Jon Holdman thanks a lot, I didn't know that there is a clear wear and tear limit for carpet at 5 years, very useful info!!  

Unfortunately though, the supply appears to be rather limited in the Jacksonville area and most of these properties are located in what appear to be questionable neighborhoods - class D. 

You may be able to get into something there-there are a lot of owner occupant loans with very favorable terms and they are not just limited to FHA.

If you buy in a suspect area you are really limiting your buyer pool to investor buyers.While the strategy with this property is to sell after the rehab is complete and 2 of the 3 units are filled with tenants, we currently hold 25 units in our local market here in CT and the highest amount of units in a given building is 6.

My only suggestion would be to make sure that you are accounting for all expenses/reserves, including but not limited to the below.