Have a late fee in your lease.Leaving trash in the yard, tell them to clean it up because if the city gives you a fine, who do you think is going to pay for it?

They have been managing fine, although not too busy, I guess because of the market.

If credit scores are fine, and you are just new to the work sector, then I would suggest doing a conventional loan with a strong income "non-occupying coborrower". 

For every angry client we have many more that are doing just fine!

The rent will be increasing by $100 and I'm just wondering if it's fine to request a check for the additional $100 security deposit or if I need to withdraw and return the current security deposit and request a check for the new amount? 

My realtor told me that there's been happenings of neighbors turning in people who are doing STR's and getting investigated by authorities, resulting in fines & such.  

If it is a larger bank/mortgage broker, you should be fine. 

I’m 37 and I’m wanting to do real estate full time eventually(if it takes 5-10 years, that’s fine). 

Yes has long as you are worthless you’ll be fine.

Logically I can't make a solid business case to cancel them, as the cash flow is fine vs losing it all with a tornado.