If I buy a multifamily apartment complex, am I required to bring it into compliance with building codes?  

The up side for her is I will end up buying 5-10 properties a year through her.My only criticism of her is she wont bend the rules and give me the lockbox codes so I can look inside a property on my own, if I happen to be driving by. 

No wetlands, it is zoned RLD-60 and is big enough to make two lots conforming to that code. 

HUGE discount probably in the neighborhood of 40 to 50% less than principal balance

If you want to build anything more efficient than a minimum code bundle of sticks, you could be looking at $120 - $130/sq ft.  

I'm getting all my closing costs paid for, 4% discount, and I'm doing 3.5% down.

And that house in Maryland in the 21146 zip code would have been $ 475,000 done .

While researching the property, sales records and owner info, I discovered the seller also owns the house next door to the one I'm interested.This is when I had a thought.How can I get in touch with the owner to negotiate a package deal for both houses at a discounted price?

You are about 5 years late for those kind of discounts in the greater Raleigh area.

Our local rental association in Clark County publishes a great tool called "State of Washington Residential Rental Laws" that puts into one place all of the RCWs (RCW = Revised Code of Washington) regarding residential rental property and includes a helpful summary.