Oh and I have another one that is mf that I think we got checks maybe 6 out of 12 months..

Definitely recommend checking out local REI meetups in Boston now and Chicago later—tons of value in connecting with local investors.

And what if the one person you didn't check has a criminal background, has collections, and more?

I lived for free for a couple years, while collecting rent checks. 

Here are a few suggestions on how you can maximize the wealth of information available: Check out the blogs and podcasts, or take advantage of the search feature (magnifying glass).

You can simply request a separate check for the $100 increase to bring the total deposit in line with the new rent amount.

If you plan to manage remotely, then find a good PM or have a trusted team that can inspect your property regularly - and be ready to pay them.

Quote from @Joshua Alcantara: Quote from @Peter Walther: I've found many properties with title issues wind up with unpaid property taxes so checking on delinquent taxes, tax deed sales and lands available for taxes might help you identify some.Thanks, Peter, for the info!

Have a way to double checking their information they give you on the application.  

Check out the rookie podcast forum, you will gain a lot from it.