1, 2 – It’s possible to setup via “Edit restrictions add-on“. Activate it, then open “Edit post” dialog for a role and select “Own data only”.
3 – You had to use as a base role for the starting point the contributor role, not the author. Revoke from a role these capabilities: ‘publish_posts’, ‘publish_products’, ‘edit_published_posts’, ‘edit_published_products’, ‘delete_published_posts’, ‘delete_published_products’.
4. You can not control with URE what fields are shown at the front-end product page.
