How much was in JMS's pitch/package to Paramount? Did he include every single trap door and branching storyline? The series was originally about Sinclair,. Instead, they just moved that up and crafted a totally new ending for Sheridan IIRC.who was supposed to end up turning into Valen at the end of the series
Nope. That's a common assumption that's completely wrong.
There was no mention of Valen in the original series treatment at all. Nor in the synopsis of the show & spinoff written between the pilot and first season.
As for what JMS gave to Paramount, it would be the series Treatment, the Pilot script, some concept art by Peter Ledger and probably a dozen or so episode pitches.
As for another poster's comment about a shapeshifter, the early drafts of 'The Gathering' did indeed feature a shape shifter which was changed to the assassin using the changeling net at WBs request. But it would pretty certainly have been in the script accompanying the series treatment.
Jan