once you pare down the definition to the basic essentials of what is really meant and stop being confused by the language used to traditionally describe free will, that you should in principle be able to have a deterministic agent who does, in fact, have free will for all meaningful purposes.

I don't read it this way. The approach you linked to basically says that free will does not exist and is just a concept humans came up with to confuse themselves. If you accept this, then you should not use the "free will" terminology at all because there is no point to it. So I still don't understand that concept.