When i was rehabbing properties full time (2011-2014), I also always aimed to set my re-sale price 5% shy of market price.

So I wanted to first set the criteria of about what an average price point should be to start.  

We have a separate LLC set up for each of them and a separate business checking account to collect rents, security deposits and pay SOME expenses. 

Now you can write up a business plan and set a realistic goal. 

So really the answer to your question is first to define a set of criteria.

I was considering a property manager but I really don't know if it's necessary  as long as I could set up some sort of automatic payments with the tenants.. 

And can someone recommend good and inexpensive (or should I say not too expensive) CPA and lawyer, knowing that I don't want to spend a lot of effort and money on setting up a structure for what could be the only operation of this type we ever do?

The point John was making, I think, is that the depreciation and other paper deductions that you create by having rental properties, can help off-set your SEI, and any other income for that matter, as a 'real estate professional'

as an aside, both of our credit scores are excellent so this helps.

Then I had the thought that if we just went with simple keypads (programmed only on site, we keep the backup physical key), we could require/help each tenant set their own code at move in.