I work in architecture and used to work construction.

Architecture fees alone ar going to run you 5-10% on construction cost.

Although I don't have direct experience with the firm, a relative of mine had a positive experience with Design Styles Architecture out of Tampa. 

Germantown has great architecture because of it's Quaker/Shaker heritage but also has some of the worst hoods in the city.

should it be modern design or just something that fits with the overall current architecture? 

That's way beyond architectural or building standards.

This may be way too late, and I see many takes on the topic here but here is my two cents as an architectural designer and agent; do what makes most sense for your audience.

We own an Interior/Architectural Design company and have designs that would work on these lots, as well as people in the area that can help us with construction and property management, but we've been wondering if it would be more lucrative for us to invest in mobile homes to start out instead.Does a Mobile Home work out as a STR? 

Hi Alex,I'm the Director of Architecture and Interior Design for DAT Group. 

However, we also have an architectural firm so we kind of cheat by asking for tons of advice from out network.