q1: yes. this is possible. one can define a policy with the "role" creator, such that only the creator (and the admin) has rights to perform certain operations. This is independent of formpages and works for all kind of of xowiki objects. We did last year the conference registration for the Vienna OpenACS/DotLrn conference based on that.
q2: currently, one can subscribe either the whole xowiki instance (via package_id) or a category (subscribe to changes for pages having this category). It should be possible with moderate effort to add subscription for single items. Having this, it should be technically possible to auto-subscribe admins and owners for certain items. But both steps are not implemented, maybe there are better approaches to reach this effect.
