For your first example, it is unnecessary to specify "for" as an attribute on rich:tooltip as it is automatically associated with the parent component.  An example of this is part of the RichFaces Showcase portlet in PBR.

With the second example, we don't currently have an example of that approach, so am uncertain as to whether there may be a bug with using tooltip that way.  One thing you could check is whether the target on the tooltip is updated to include the portlet namespace, otherwise it might be that the ajax in the tooltip doesn't have the correct id of what it should be rendering against.

Ken