Are you self-managing? 

In effect, you will end up paying tax on your refi cash later on, when you sell the property.

My son (age 24) however, is an independant contractor / self employed and is trying to buy a house. 

The Retainer Fee is credited towards whatever they buy from us in the 90 days, so in effect, costs them nothing.Note: we're not doing this to make money, but to avoid the time-wasters.

Finding a good account and bookkeeper wasn't difficult and using online registered agents was way more cost effective.

Do you have any pics of some of your favorites (before/afters would be nice).Maybe some curb shots, and an interior rehab your most proud of.Do you self-manage/collect the rents yourself?

The STR part plays no part in the valuation like @Patricia Andriolo-Bull said.I agree that 20% is pretty fair, but you could self manage it once you get things in order.

Start with books and self-education before considering any paid courses!

In neighborhood it is very important to present your self to the home owner next to you, this helps a lot to prevent misunderstandings. also this shows your professionalism.

I agree that the best way to make money is self manage your short term rental (not AirBNB, that is a platform).