Case-by-case basis. If they only show up for a couple of scenes, then I don't name them. If they are in a couple of chapters, then yes I'd give them a name because it be too much of a hassle to constantly call them by their adjectives, titles, or whatever.
In ROTGC I tried giving them names of commenters. Though really imo there's no reason to give a name at all if it's a one-off unless the POV is supposed to be well-connected or a social butterfly.
I N̸̛̗̤̞̞̻͇͔̤̯͎̉Ą̵̠͕̗̬̀͂͛̇̃̑́͐͝Ṃ̶͉̥̻͎̪̘̗͑͑̃̑͌̇̈́́̿͆Ẽ̷̮̰͈̯͇̰͎͍̾̽̓͌͘͘͘͜͝them. They are my ̷̛̛͇̲͓̗̪̪̬̯͔̖̺̯̂̀̊̑́͘͝C̶̠̳̔̓H̵̡̗̜͔̼͍̻̳́Ị̵̱̗̝̪̙̦͕́̍̃̂̌Ḽ̴̢̒̓͒͠͠D̷͚̝̫̍̎͠R̵͚̣̐̿͑̈́͛͒́̐͒̄̕̚Ĕ̸͉̭̳̻̹͔̝̽͂N̵̗̠̪͎̉̈́ ̴̬̠͕̓. I shall shower them with A̴̧͖̯͇̠͓͓̒̍͛̉̑͆̈́T̷̨͕̥̘͉̔̒̚͝T̴̨͕͓̝͓͉̫̳̾͋́̓̇͋̄͐̓̓͂̚Ẽ̴̱̮͕͕͙̲͔͓̠̯͙̰̅͛́́̋͑̀͗̕͠N̴͚͚̫̭̙͎͈͇̗̾͗̽̈́͆T̷̻̭̲͓̉̒Ỉ̷͔̕O̴̧͖̟̦̼̐́͗͛̌̀́͌̾N̸̡̨̨̳̜̼̪͕̟̞͂̆͂̉̿̋ͅ for a greater ̵̣̀̀͆̓ͅS̷̢̟̰̞̺̲͓̱͋͒̇̂̂̎͑́Ą̵̖̖͉̀͋̍̂̃̿̆͜C̸̡̥̱̞̦̼̄̐̂͋̀̉͂̀̕͘R̵̠̬͗̒̃̅̉̆̋͋̀I̶̲̼͚̫̙̟͓̼̾F̵̢̙̣̊̿̓Ĭ̶̛͙̳̞̼̥͘̚̚Ć̸͓̤͕̠͙E̶̢̧̩͈̗̩͓͓̭̓́̃̀͝ ̴̧̲̱͙̩̣͔̠͎̘̻͓̓̏̇̂̈́͠, for my story to inself myself into.
I've named characters that are only going to be present for a single chapter.
I'm partially helped along by the fact that I went to the high-bar background work of creating my own custom language for my world. This has a fairly nice fringe benefit of making it insultingly easy to come up with name after name.
I had a funeral scene where I listed off 18 people who died, all by name. Literally that single mention of their name would be the only time in the entire series the name would come up, and I did it anyway. Again, because I was able. It really is just that easy to turn out names if you've invented a custom language.
Depends on the situation. If someone is going undercover, then yes, I'll use the name, or if I am introducing someone new who, even if they might die in the next couple of chapters, I'll also make a new name for them.
i usually give them a goofy name i choose by looking around and choosing the first object i see and change it up a bit.
Ex:
Boutor Beatil, Heath Fundtsand, Guetsby Faun, Toin Rett Paper
water bottle, headphone stand, USB fan, tolet paper
I only really name characters if they are referenced multiple times. If they only appear once in the entire book, I'm probably gonna leave them nameless. If they appear several times a chapter, Im gonna name them, even if they disappear by the time the next chapter comes around.