It is defenitely biased, because many apps have a relatively low rating, some under 4 stars, they may also take into consideration how many downloads it has.
lol what? 5 apps? i dont know some of apps they should pick one app is good then add it to editor's choice like FF addons recommenced thats a bad idea tbh
I don't have access to the editors' choice apps, but all the editors' choice games have been verified by Play Protect so I'd assume the same for the apps.
I doubt they've gone through more comprehensive security testing than what all apps do before appearing in the Play Store though.