Other than the tools they have access to, how do I know if I can trust them in looking out for my best interest?

Current slab can be removed with hand tools, concrete can be bought by volume or prepared on site. 

Since you are a pro, use the calculators provided under tools to help but here is my quick rundown on a post-it:Buy = $80kRehab = $30kHML Points = $3kHML Interest = $3k (assuming 90 days held total)Holding Costs = $1,500 (assuming 90 days electric, gas, water/trash/sewer, builders risk ins, prop tax)*Selling Costs = $10k (6% relator fees, 1.5% closing costs)Sale Price = $135kProfit = $7,500*I am taking a very high level guess on your holding costsFor me this is WAY too thin of a margin.

I'm trying to use the tool from bigger pockets, smart move with transunion but the website has not been working the last 3 days that I've tried to use it.

Does anyone have a useful tool to carry around keys that isn't just a standard key ring?

I'm intrigued by this option, but also the word "balloon" gives me heartburn, although I know from reading on here that it can be a valuable tool.

Leverage is a tool you can use for acquiring more properties.

I am confident that I have all the tools I need, just needing to expand my knowledge and network!!

Intimidation is the most valuable tool a landlord can bring to the game.

I would suggest you set up a website also with a nice clean simple landing page to generate leads.Then you can direct your Facebook Ads or Google Adwords campaigns there and it also ads credibility.Twitter and Instagram both have paid marketing tools as well that you can utilize to build an online presence.