> 1) indicators must go to the top right of the screen no possibility to change it.
> 2) indicators must be in a fixed order, no possibility to change it.
That's a detail of the implementation planned by Canonical, I highly doubt that the API/specification mentions such stuff at all. Ie., if Ubuntu ships with an implementation having fixed position and order, there's nothing stopping people from creating an alternative, compatible, implementation making this customizable.