I see the main thing I wanted to ask about already exists: https://ask.clojure.org/index.php/7843/allow-specifying-aliases-coordinates-that-point-projects

Does it work to specify a default dependency in the root deps.edn and not specify a coordinate in aliases to use it so that you can ensure that all aliases use the same version?

I'm not sure I'm following the question, can you use a deps.edn to demonstrate the question?

I think by "root deps.edn", you actually mean the project deps.edn? (the root deps.edn is the one included with tools.deps)