I understand this is not a requirement, but I have never received a damaged unit from an inherited tenant or any legal issues.

Both of those websites charge the tenants more than $25 and we require all adults living in our units to pay and fill out an application. 

Which is not easy for possible for many people (like your husband).Once you really know what to do, the risk level drastically reduces.

Ask how many units they manage and how much experience they have.

My thoughts are to have a fire pit area in between the units since each will also have their own terraces.  

congrats on the first duplex. easiest will be house hack your next property. you can go higher in units up to 4 but just need to occupy the property. lets connect if you need guidance, i house hacked a few times

Haven't been there, but pay attention to the foundation - if the floors are level there no action needed.

Are we stopping landlords from acquiring 1-4 unit properties going forward to keep the supply available for owners occupied owners?

Is it single level?

If you offer incentives to fill units will they fill the units with subpar tenants?