I think I describe the workarounds quite well in the document.
Just specifying an explicit noun is enough to override the "ID represents the adjective and noun" rule. Or adding a numeric suffix.
The id doesn't have to be tied to the noun, so reserved words don't stop you from making as many roots or backs as you like.
Yes, back is reserved even outside of gamebook mode for the sake of simplicity and because gamebook mode will overlap parser mode optionally in future revisions. I was just setting the flag down early.