I just acquired a 3 unit, and i figured i have to protect my asset by registering it.All suggestions are welcome.

That being said, what protection are you looking for when purchasing a property for yourself or an entity your a part of? 

Most tenants do not have an issue supplying them.If you are developing a tenant screening app you would need to remember who your customer is, the landlord, not the tenant.

We also had some customer service issues with them. 

Being Section 8 isn't a protected class.

If you are flipping, then the S-corporation is probably better.In my opinion, a business entity is not really necessary until you have a high net worth to protect but this is not a widely held opinion in these forums.  

It's probably worth 340k to an end customer as a single family, 1600sq ft, 4bed, 2 bath, remodeled.

Yes they may get orders to transfer but that is life (anyone non military could lose their job or get transferred which has the same end result for you) and they are protecting our country with little pay.  

He is a contractor who does sub work for high end custom homes here (his primary trade is finish carpentry) though he can do the gamut of tile, drywall, siding etc)  I'm also capable of a lot of this work though I work better assisting someone else, some I can take the lead.  

I know they say do business with folks you trust, but at some point the numbers warrant protecting yourself.