Over the next three years, we will invest approximately $4-5k to update the units to modern expectations, and be able to see a healthy rise in rent and reduction of time to fill.

So, we're preparing a packet to be sent the old fashioned way. 

Anyone have experience with VAs in this fashion?

You will need to find a broker who will let you do that as most just want you to sell and earn commissions for clients in the traditional fashion.

Call me old fashioned but my accountant and attorney have real offices and if we are going to be continually trying to elevate our image and level of professionalism we need a physical location.

Those of us that have been in the game for a while and had no other choice are used to doing it the old fashioned way.

I have seen some really nice ADUs built nowadays (2 stories with balconies), modern, each with own utilities (even water).

Zoning as it is today is a fairly modern phenomena and in the not too distant past what could be build was what an owner decided was best (over simplification but somewhat valid).

Making small updates to make it a little more modern and functional.

Won't change their mind but you'll be on the record in the appropriate fashion.