Go conservative ) - Holding Costs (loan payment, utilities, insurance, etc) - Rehab Costs (you will have a good handle on this) - Closing Costs (you will pay closing costs on both purchase and sale of home)  - Profit (minimum you would want to take on the risk.

In Colorado, we also have the HUD FMR but each PHA will publish its own Payment Standard and Utilities Standard for what they are willing to pay on a voucher. 

Even if you prefer not to include any utilities often as a landlord you are better off including utilities provided by the municipality.

I utilize these products but more for commercial multifamily where they build in an interest only period, 30 year amortization schedule, and the bank funds as much as 100% of the construction costs.

You will need a zoning permit, possible streets approvals, utility plans, excavation plan, building permit, MEP's, then sub contractor permits for all of the MEP's.

By your own admission you don't have a budget to utilize some of the more expensive marketing systems.

I'm 31 I never met one person who moved to Lehigh acres under 50 years old. no jobs, infrastructure, commercial, etc and no utilities either. just a land play that a developer made millions on in the past 

We’re probably the only designers and contractors who would say no—unless you’re in the luxury STR space.Why?

Also you can save a lot of money if pm has their own handyman employees and do not need to sub out all repairs. my experience is that STRs outperform LTR by enough to cover the PM fees, utilities, and additional furnishing costs but not much more.  

I have a few properties in high traffic areas with at I plan to utilize by putting up some “we buy houses type signs”.