1. There was a reported bug for png/pdf creation with version 2.0 (search this forum). Until version 2.1 is released onto sourceforge I would recommend using war from people.redhat.com/tsurdilo/designer/master as that issue is fixed there (and many more :) ).
2,3,4 Please raise Jiras. You can do a quick Jira search to see if anything exists but I would rather have duplicate entries than none at all.
Thanks.