Fedor Koleganov

Not that I know of, but look for the usual suspects like Attribute/Group Paint, frozen nodes, Stash SOPs etc. I did file an RFE about a year ago for some kind of scene analyzer tool like that, but no luck so far.

Looking at Changelogs, it was already fixed in a daily build.

The selection is not based on ids by default because id is not an intrinsic or required attribute, you won't always have it. The cleanest way I'd say is to create a point group with a Group SOP using "Keep by Random Chance" parameters that does accept seed attributes like id. Then you delete the group with a Blast SOP.