[throughnothing]

I think saying a sysadmin 'cannot work on developing the product itself', is silly. I think it's a given that anyone joining at such an early stage of a company is going to be developing the product. You will definitely need a sysadmin that can develop the product and move fast. Your architecture is part of the product, and the sysadmin should help with the design and implementation of the architecture, as well as possibly parts of the codebase going onto that architecture.