Redmine

First thanks for all of you. Redmine is great !
I use it since 20 days and a lot of projects are now setted.
Some projects need particular trackers (and Issues statuses of course) and i need some functionnality not yet available.
So i register here to ask you if it's possible ? My projects are not all source code projects ...

My questions :

1 - I can't set a default status to a particular tracker. The default unique status is set for all trackers.
How to do this ?

2 - When a project use particular trackers, statuses of all trackers are shown in the filter search parameters for issues.
How can i hide these statuses if my project doesn't use them ?

3 - It will be great to add observers directly on submitting a new issue ! Why not ?

I'm using Ruby and Rails at work. I can try by my side to modify the source code to match my needs... but you, as author, could help me first ??
Thank you again.