I’d appreciate any feedback on whether tools like this would be valuable or if other concerns take priority.

You're spot on about security deposits being a practical tool to mitigate risk, especially with applicants who have checkered rental histories.

I think special tools are needed in this instance. 

I think I am on a path to recovery, ready to check out the market tools to finally pick and market and find some deals!

@Guifre Mora isn't drop box just a file management tool?

BP has various tools to help you analyze your deals (rentals, flips, wholesale, etc). : https://www.biggerpockets.com/investment-calculators7.

We use Key Data Dashboard, a superior analytics tool used by property managers, DMO's and similar organizations.

For analysis, you need to identify a market that interests you using tools like AirDNA, Mashvisor, Pricelabs, etc. 

I would disagree with number 2 - in this environment, heavy rate buydowns are a common tool in the toolkit for lenders and borrowers to make deals work and are in no way indicative of "not being well-capitalized"

Although I have not yet purchased my first tax deed property, I have been spending a considerable amount of time researching the tax deed sale process and the tools that can be used to streamline the process as much as possible- one of those tools being PropertyOnion.com.The website seems to provide a wealth of knowledge for pretty much any property you'd like to research, and provides data that could be useful to a variety of RE investors.