Using tools within Renoise is one thing, using renoise is a CLI tool yet another.
The best (i.e. the most complicated and fun to program) way to do something similar with a tool would probably involve running a Renoise instance as some kind of “server” ( https://github.com/renoise/xrnx/blob/master/Documentation/Renoise.Socket.API.lua ) that listens for commands via GET/POST requests and batches them (since it can’t render two songs at the same time). It would render those to files, and maybe allow requesting those via GET, too.
But what if there is a popup because of a missing plugin etc.? Can tools handle that?