Q1. At this point, I think that would be a feature request. Since inception, Attribute Browser view hasn’t supported multiple selections, possibly due to the way the main view is composed of lots of per-value sub-lists . In the past that had little effect, though of course that predated the new featutre of showing combined $Texts for the selection.
Q2.1. It is not possible to store queries, for AB view or for normal agents.
Q2.2. Action code doesn’t have commenting method.