and if what is being described is true and the OP is simply a wholesaler then  its on to the Next full stop end of discussion.

I wrote an article about this a while back you might find helpful: https://www.biggerpockets.com/...It references an old study from the 90s, but I think it's still more or less true and a good starting point for this discussion: In 2003, the National Association of Realtors came out with a study on the characteristics that increase and decrease the price of new housing (assuming all other characteristics, i.e. square footage, remain the same).

The same is true with your question regarding rent raises.

The old saying you don’t know what you don’t know stands true here.

Might be tough to get financing for resale as many lenders have restrictions about one owner owning more than 20% of the units in one development.Very few condos work well for rentals due to the HOA dues, so have to be careful there.You would think more 1st time home buyers would be looking at condos to buy due to the lower prices, but so far not sure that is true.

Something I specifically am passionate about is helping other people, so naturally I am excited to be a landlord.

That's the world of foreclosure auctions (true ones like your's, not the silly websites).

Or are there classics that still hold true for today? 

It looks like you've been in contact with the seller and may have a gauge on their true desire to sell, which can help you determine whether the $600 for an appraisal is money wasted or a worthwhile risk.My supposition is the appraisal will come in higher than your offer, which will likely embolden the seller to stick to the appraised value or higher.

Their true vacancy rate was roughly 13% not 1.5%.