There are definitely some great areas in Oakland, and condos aren't subject to rent control, unlike an apartment building.

Or you may be able to sell it, subject to the buyer assuming your relatives loan. 

Great deals are subjective to your situation.

It depends upon your strategy and what you're looking to accomplish both short term and long term.The issue with using a HELOC for long-term financing is that your interest rate is subject to change over time, unlike a fixed 15, 20 or 30 year mortgage. 

There is no apparent pain here for you to remove from their life.That being said, if the sellers would enjoy a superior steady income without the liability & management that comes with property ownership tenant, you can make a case for them to let you buy the how subject-2 their 1st TD.  

I would separate the subjective from the objective first.

Use zillow to get the comps you need to come up with your own estimate.To me, I have a pretty simplistic approach to estimating.In Zillow, I enter the address of my home and click submit.I then modify the default filters based on my subject property's key characteristics: Bedroom count, square footage and age of home. 

Short term capital gains are not subject to self employment tax, while ordinary income can be subject to self employment tax based upon the source.Talk to a CPA, happily pay for the consultation.  

This property is in Florida and I welcome any opinions on this subject.

I'm in a similar situation, as I just began my foray into REI after spending a 3 month honeymoon reading, writing, and soaking up every introductory nugget of knowledge on the subject.