Regarding financing (and sight distance approval), maybe having your architect make up a small model with people and cars to help sell the project to the bank.This could be costly and of course there's no way to measure the effectiveness on their decision. 

Another option is to find a good local architect, civil engineer, or similiar third party consultant to take a look at it and let you know their thoughts on the viability of developing it. 

I don't ever look at land to subdivide just entitle it to the max. add units, etc. or buy land smarter. it's not hard. you can handle all of it yourself but you need a good architect or overseas drafter who knows their stuff. 

I would start with the architect and knowledgable agent to know what is going to give you the biggest return. 

We lost earnest money, appraisal fees, money spent on the architect, money spent on my attorney, and much worse, the loss of profit on this deal.  

Investment Info:

Single-family residence buy & hold investment.

Purchase price: $650,000

Cash invested: $240,000

I bought raw land ($170K) and designed the home and managed the construction. The ...

I'm nervous because I've never had a business before and I still have a full-time job as a cloud solutions architect, which I'm really passionate about - so hopefully it won't be my golden handcuffs that may prevent me to thrive as an investor and  I'm excited because of all the benefits and freedoms being a business owner offers, one of which is to connect and collaborate with forums like this and people like all of you, where I can both learn from and hopefully share later as I develop more experience. :-)

We would like to do it all legally with plans approved by the town.Any recommendations for an architect / company that can assist us with this project? 

You get grandfathered into the codes that were in place at the time, you get the old setbacks, you don't pay an architect, engineer, city and permit fees, plan check costs, school fees and other costs that will not come with an existing house.Not saying that you can't build new for less than a remodel, but not usually when you add in all the costs above. 

You may need a building permit to install signage and depending on the area you may need an architect's drawing of it.