For instance, one property seems to have an extra bathroom that is not listed in the county records.I plan to make some modifications, including removing a closet wall to expand a bathroom and taking out a kitchen island that contains electrical outlets and a switch.

And this does not include the real world issues, namely are you even allowed to convert this property to a four-unit and taking a single family to 4 unit is very likely going to cost more than $110k (but this depends on the actual layout and work scope).

I think I had 14 of them not including my home..

I agree with everything @Michael Baum said.Many people, including myself, have used a 10% down second home loan to buy a property used for a STR.

This contract includes an exclusivity clause to prevent your clients from bypassing you and going straight to the lenders to cut out your commission. 

I am expanded my door knocking operation to include other people within my company.

@Chirag Mehta For construction costs, you should be around +/- $100 PSF which would include all sitework, utilities, and going vertical with modern finishes.  

However, strict IRS regulations apply, including prohibited personal use and mandatory income and expense management through the IRA, with penalties for violations.

Pull comps, if you rent it for 1500.00 you are cashflowing 120.00 a month with all the info you gave me and including fees except if you take any fees on (water/trash etc.

If all else fails, 😀 ReSure's got extensive resources on all these subjects in our educational platform (which actually includes some plagiarizing from Michael!