Personal opinion, ive never liked dual-agency.

Own money How did you add value to the deal?

Coming from someone who's owned 7 duplexes, and about to build another (pm me if anyone is interested!)......

We provide our personal golf cart to guests staying at our STR and it has been a hit and sets us apart from others. 

Paul the owner basically handles everything so there is definitely a personal connection. 

She stated that she owns a home but recently gave it to her children and grandchildren to live in with her most recent rental history claiming to be from 2017-2018.

I currently have a few single houses for rent which are directly under my name, and also the mortgages are under my name.I am considering to move the houses to an LLC 100% owned by me.

If you cash out refinance you incur (more or less) all the lending fees associated with a financed property purchase (even though you are just refinancing the property you already own), and then you incur significant fees when you sell the property (closing costs, commissions, etc).  

Or what if you personally found home you want to buy without a real estate agent...is it recommend to engage an agent?

Some cities in MI have this but there is always the alternative that if you do not live within X distance you need a local rep/manager or person for them to know about and be able to call.