It sounds like you've done a lot of the preparation work required to hit the ground running. 

Definitely sounds like an interesting asset class.

You’ll want to get really familiar with local zoning laws, short-term rental rules, and landlord-tenant laws as they vary by town if you plan on going the STR route.Focus on Cash Flow Early On: You might be tempted to go for something that appreciates quickly, but in the early stages, it’s important to find properties that bring in cash flow.

Your focus on the Dallas market and Fix and Flip projects sounds solid, especially with the DIY approach and having an interior designer on your team. 

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.

Sounds like you guys have the potential to be an amazing property management team!

This sounds like Section 8/Voucher tenants, is that accurate?

A great lake front home doesn't have to cost a mint but it sounds like you want something that is really fantastic which will bring a higher nightly rate.

Sounds like you are better off in a high yield savings account like @Dominic Mazzarella mentioned...Just out of curiosity, Nilusha, what Chicago neighborhood are your 2 flats in?

Given their age and position in life… mailbox money flow forever sounds like a good start to retirement to me!