A 400 unit residential complex is essentially a multi-million dollar business - if you have experience running an enterprise of that size, then you will simply/only need to become familiar with a new business sector.  

Anyone know an attorney/firm with that proven expertise?

It's all well and good to hire a broker, but if you are setting the price, or not listening to the broker, you won't get anywhere.That being said, you pay the brokers for their expertise.

I'll preface by saying I'm a CPA but don't let that fool you as I was just a former auditor with probably no more expertise in taxation than the average Joe. 

I'm gonna lean on the expertise of my Realtor to help me lock into the right neighborhood here in the Phoenix market.

Being a "newbie" I don't have a great deal of expertise to provide but I am committed to contribute to the BP community where I can. 

It's like all DIY, it depends on your level of expertise and comfort zone. 

If your search criteria fall into my geographic area of expertise I may be able to provide you with some off-market inventory as well. 

I'm specifically interested in learning about the MFR sector, tax strategies, hard and private money lending, BRRRR, short term rentals, SDIRAs, and other investment markets.2) BRRRR. 

Don't be afraid to ask your agent tons of questions, I'm sure he'd be glad to provide his expertise in those areas. and be your eyes on "The Land" lol.