I saw once where a developer gave the buyer a pass on paying HOA fees till a house was built on a lot. 

LOne common strategy is doing a cash-out refinance on one of your rental properties to tap into the equity.

However, I don’t yet have the funds for a down payment on another house, and I’m trying to figure out the best option for where to live while I rent the apartment.Do you have any recommendations for managing this transition or tips on finding a temporary place to stay?

Focus on the numbers rather than emotions.

The theory is spot on, in practice however that logic rarely plays out - at least in recent years where multifamily has been crazy.

Then they make a **** load of money on them, and still collect on loans  which they never make (plus interest). 

Which will also depend on the neighborhood.You want to, "rehab/maintain to the Neighborhood".Most investors go overboard on their first rehab and waste a decent amount of money.

There are many resources for you to connect online and in person.

I'd love to talk and get you an offer on it!

I think it would be better just to stay on good terms and let him know you will contact him when you are ready to sell.