I think it makes a lot of sense to split these up sensibly, I'd propose something like this
Do we really need an app-blocking tag? The one question that I think you're nominating for it, is really a PC question rather than an Android one (and quite an edge case even there) I'd think it would be better off on SuperUser than here, and even then I think "locking" is probably closer to what is happening than blocking (seems to be to do with locked handles on mounted drives/files).
*I'd think that call-blocking should be set to a synonym of call-screening (as surely blocking is just a type of screening where you don't allow the call through after screening it). One of the call-screening questions even mentions blocking in the title.