Converting a 5,000 sq ft. office building to 3-4 apartments

[Bob Bevis]

I've searched the forums but haven't quite found what I was looking for.  In this hot real estate market, it's been harder and harder to find good deals.  An opportunity recently came up that I'm excited about but it's a little outside of my normal buy and hold investments.  I'd be looking at acquiring a 5,000 sq ft building that consist of a single 2 bedroom apartment and about 4k sq ft of vacant dated office space and converting the office space into 3 additional apartments.  There are about 4 bathrooms in the office space, electric and lighting throughout, 3 heating systems (1 in the apt and 2 for the office space).

Today the zoning is commercial.  A couple of concerns come to mind that I need to figure out the answers to:  

1. Zoning - will the town grant the variance to convert the entire building to apartments.  (initial call into them suggest that it may not be a problem) 

2. Septic - the current owner doesn't know what is in place but I'm guessing it will need to be re-done or updated to support 4 total apartments.  

3. I'm thinking that I'll need to hire: Architect to analyze and design the best use options and building plans? Attorney to present the plans to the town board for zoning?  Contractor that can handle this type of renovation?

Rough numbers - I think I can pick this up for about 350k, I'm estimating about 150k in repairs/remodeling.  I should be able to get about $6,500+ in rents once it's done.

What else should I be thinking of?  I'd love to hear from anyone that's tackled this type of project before on their lessons learned.  Thanks.