Even with below market rents, I though it was unlikely that I would be able to even match the cashflow I'm getting currently- because we're not paying a mortgage. 

I wanted to become a full time passive investor anyway, so this fit nicely with my goals and objectives.I think one of the most important things to think about when making these decisions is if the investment strategy will match your lifestyle - if you really want to retire and not think about your finances, perhaps the DST will work best for you. 

I’ve been going through recently filed Probates and matching them up with their properties.

The only down side with Zillow is it takes about 5 - 7 business days for the funds to be deposited into your account once collected from your tenant. 

This potentially caused us to lose out on a few other tenants who were ready to begin the lease ASAP, but we decided to go with this couple because they had better credit scores and financial situation.Does anyone have any advice on ways to prevent this from happening, such as including a fine for people backing out or requesting the security deposit upon signing of the lease?

I assume you required a one month damage deposit.

I like MTM with first, last and the security deposit up front-makes for a respectful tenant.

I had a few questions if you all wouldn't mind giving us some tips.We want to find a good and free bank account for rental payments and security deposits. 

I tried one of the 5 the normal way with everything almost funded but it was a huge pain with the drawers (they deposited with checks for some reason so it took an additional few days to get the funds) and I had to deal with a super lame system to even get the drawers sent over.

Locations are not important as long as they on board remotely/online and have a strong "online friendly" presence that can satisfy most general banking needs (attractive ach fees, online check deposit, ect).