I read a comment under a Youtube video the other day, that The Hardest Part Is The Night was written by Jon in 1982 before Bon Jovi. A demo version of that song should also exist in the bootleg world.

Since the recording process of both Slippery and New Jersey is documented pretty well, there's only very few stuff about the first album and as far as I'm concerned almost nothing about Fahrenheit.
What we know about that album: Recorded allegedly from January - March 1985 and released on March 27, 1985.
I think it's a pretty short period for writing, recording and producing an album when the first tour ended November 5, 1984 and the next tour started with headlining shows on April 20, 1985. So when was this Japanese tour booked and when went tickets on sale? Although the Japanese were much more excited about Bon Jovi back then than other parts of the world it somehow seems strange if headlining shows were booked without a new record being released yet.
Back to the songwriting. Does anybody around here know of Fahrenheit demos being around? I think we all agree, that the first album was mostly a Jon solo record with some cooperations with Richie. But Fahrenheit lists only 3 songs as being written by Jon alone. So I was suprised about that quote that a demo of Hardest Part exist from Jon prior to Bon Jovi.
So what do you guys know and think?