various repairs have different returns some like a kitchen remodel get a lot of bang for their buck, others need to be done but don't add a ton of value like upgraded electrical.

Based on current rents, average unit price appreciation, condos fees and property taxes - it would be a negative cash flow for the first 7-8 years, excluding planning for any repairs or vacancies. 

(if you PM /email me the address I would be glad to pull some data for you)...At a glance, you are completing a renovation on this property, but your expenses are sky high for operations...why would you have operating expenses for a freshly renovated property...and CapEX...logically, your expenses would be significantly lower for things like maintenance/repairs...Glad to assist further

Texas is a verbal contract state...so even if you simply said it over the phone the applicant could pursue civil action and attempt to force compliance to the agreement.2.

For minor work (i.e. quick exterior repair), I probably wouldn't bother notifying them. 

How can I go about tracking down a phone number of the owner of this property?

Water needs to be metered to tenants.Both units need repairs and remodel. 

Also, if they do not pick up the phone for you, or give you a call back in a reasonable time frame, they surely aren't going to be responsive to your tenants

Now before everyone jumps on me about, "If you sold under contract why are YOU making repairs?".

What are the needed repairs for this Duplex ?