If these numbers are in the ballpark, you have sufficient cash to buy 4 more similar properties, and increase your annual net income to ~$80K (that offers a lot more breathing room).Since you purchased your properties 2-3 years ago, I'm assuming you have very LOW rates on your notes; and therefore, I would not be in a rush to pay down these loans.

How much is owed on the 1st, how much is owed to the HOA, and how much is the home worth in it's current condition?

I agree with your premise but I suppose at this time that the opposite trend will take place - that the demand for city living will INCREASE, not plummet with self-driving cars.

It may have an affect on whether or not they accept the offer but your numbers should strictly be based on the value of the property in its current condition and market.  

In the current condition, the property may be worth $50-$75K.

You have to honor current lease.. if they seem ok then keep them.. give proper notice of renewal to your lease when that comes up and any rent increase at that time also.. if you want them to go you give them notice of non-renewal.Download your state landlord tenant laws and get a copy of the lease so you know current terms so you can have that all figured out. 

If this house were in perfect condition: with new flooring, paint, landscaping, appliances, fixtures, it would sell for between 400-420K. 

You can have multiple FHA backed loans, however you must always live up to the conditions of the loan. 

Retail from $4-8k in good condition. 

This home currently has an in-ground pool but I am not sure of the current condition or any potential repairs it might need.