This should be relatively easy. I’ve added an item for this to the backlog. Previously, it was not possible to view tasks from a filter on a kanban board at all, hence the kanban board does not show the project.
This is planned as well.
Great idea! I’ve added a backlog item for this as well, but not with a high priority. The filter syntax is pretty new, there will be a few improvements to it made over time as well.