If the design allows it, building in ADA features is nice if for nothing else bigger doorways, halls, ramps, grab bars, etc.

Think about it -- if you have 5 posts with a logo in your signature, the people who see those 5 posts will see your brand.  

For my projects, I would like to tell my GC what types of things I'd like installed like a beautifully designed double vanity sink I found at Lowe's.

I'm working with the contractor to figure out the re-design. 

On the marketing side of things, I have some experience with graphic design and advertising.

I myself am an architectural designer with over 30 years experience building so they are a perfect fit for me and they have deep pockets so I can go after bigger deals.

You may also want to hire a painter (depending on the amount needed and the complexity of the space).I've done quite a bit of that and think I finally have a good idea of where i want to go with the design.

Few things, just coming from a designers aspect.

If you have a truss roof, it may not be (though the truss may have been designed to need support).

There could also be other types of designations and use permits depending on the date of the current zoning ordinance.