Find one that can be custom to your needs, has flexible pricing, no long-term, high-cost memberships, and excellent customer services to determine how to best market to your leads.

That would be excellent! 

I have no debt, significant equity, good W-2, and excellent credit.

I have some homes in Ft Lauderdale and excel in the Short Term Rental space. 

If you need a referral to an excellent agent who works exclusively with STRs in that specific market, I can refer ours  I'm an agent, but yes I am in contact w/ one out there familiar w/ STRs. thanks for asking. 

There's no one size fits all approach to real estate investing and depending on your resources, skill set, and capabilities you may excel in one particular market or utilizing a specific strategy whereas another investor will excel using a different approach.  

Is there any evidence or support I can include to make my letter of intent more credible?

Cleveland is an excellent market to invest in real estate.

You certainly have provided some excellent thinking points for me as I move forward to owning a rental.  

FHA 203(k) Loan BasicsThe FHA 203(k) loan is an excellent option for financing a multifamily property (up to 4 units) with only 3.5% down.