2) Seam provides access to task lists etc. via EL - see the docs for more http://docs.jboss.org/seam/2.0.1.CR1/reference/en/html/jbpm.html. Of course you can easily create more such lists by creating a Seam component that does the necessary jbpm query
1 and 3 need to be asked via the jbpm or gravel forums.
tanx a lot
Although it could be amazing to integrate Seam/jbpm4jsf/jbpm forms all together :-)