I’m looking at duplex in a very desirable neighborhood, where I want to live, close to a ton of amenities.

Not the type of return desired by a non-passive investment like residential RE. 

Also, while I desire to do all I possibly can to retain the value and well being of my house, I can't afford to go crazy!

I lived in Colorado Springs for 4 years and never did more than drive past Pueblo so I can't speak to much to the quality/desirability of living there, but either way, if the numbers work - you can't go wrong.

Those numbers will vary by the extent that your units are retrofitted with these technologies, but the smart lock is the highest in the list of most desirable tech.

I competed a pre approval application and selected primary residence and got the approval for my desired amount. 

In the suburbs of Dallas where there are lots of properties in desirable neigborhoods, it's almost impossible to find a proeperty that does not have an HOA.

However, it seems that picking one property out of your portfolio with a suitable ARM is a good thing so that you can slowly increase cash flow over time if this is desirable.

I will gladly lower the rent a few bucks to get a more desirable tenant, and I will charge more commensurate with risk.

Jump up to $600 and you can get a big 4BR in the 2nd-3rd most desirable parts of town.