Level 12 - just hope you don't run into the XP bug, if you get it you can't get the 2nd javelin for now.
They fixed that yesterday and unlocked the javelin token for everyone upon hitting the proper level, shouldn't be an issue anymore
Currently only strongholds and legendary contacts are the only "endgame" we know about.
3 more weeks to announce something substantial - hope we get something
Yeah - you only can pick a new javelin once even though you sometimes get the message that you can now pick one.
But thats just a bug.
Shaper storms are still an unknown too. We haven't heard anything about those since they were shown at the end of the E3 reveal.