The agent/investors that are doing well is because they treat one of those things as a full time job and the other part compliments it.Lets address each point of your post.1. 

Not a lawyer, but I would think you’d have to prove that they did their job poorly, as opposed to ‘anyone could have missed that’.

If I have 3 applicants that have similar work history, clean backgrounds, and similar credit score, then is it okay to choose an older single person over a younger couple.I should state that the most recent tenant I did a terrible job of choosing and after just a year we threw the carpets out and filled two dumpsters with house and yard trash. 

We do some in house drawings depending on the job at hand.

Another option is to speak to the city and see what kind of support they can offer.Where is this community located and is there potential job growth and a sustainable economy in the area?

With a house that big, I would say about 100-120k would get the job done unless you need to do major mechanical updates!

I'd like to take a part time job as a  onsite property manager. 

I have a very good relationship with them, and they have done a great job for me.

This may be a good consideration when searching for a condo, as contractors will give you a bid based on the difficulty of the work, as well as the requirements needed to get the job done.

Hi Vincent,Great job looking for those types of returns.