Being able to rent them out gradually can help the vacancy situation, but it also limits what hours you can work in the other units once there are tenants.Seattle to Tacoma is a haul, I am spoiled with all our units within a few miles of us.

Since there is a limit of 4 total houses in getting conventional loan, would this commercial loan of 5 units close doors on me for getting conventional loans for my future acquisitions?

I have some limited access to cash, but in the "analysis paralysis" phase and hoping to get over the hump soon. 

Ok, I know my limitations and as a first venture into RE investing, this isn't anything that I could do; however, I know of at least 3-4 investors that could potentially be interested in this; however, there is a tremendous amount of due diligence I would need to do, before I brought it to them to view.Unfortunately, I saw this property about 6-8 weeks ago, and I looked it up, and saw that it was owned by what looked like an investment holding company of some sort.

Publication 463 clearly states that the 50% limit would apply in the first three cases."

Limit surprises/risk and subjectivity.  

Also keep in mind that rents are rising pretty quickly in the right neighborhoods so that 5% cap will be higher in the future.I've only got limited experience and got very lucky with my first MF purchase thus far (800K for a 4 unit in a very hot neighborhood with a current rentroll of ~$7K that is still about 10% below market) but I think the same advice applies here that would to most places - keep digging and get creative.

I'm having difficulty finding companies that provide such a product and getting limited offers from my broker.

Remember that after filing, whether a summary probate or a formal probate with full IAEA authority or limited powers, your seller will be solicited by others (maybe even me!).

So, with limited cash and a desire to use an FHA loan, you should be looking for smal multis - duplex, tri, or quad.