If they are single, not too long hairs, I think so. Eyebrows are also similar, and it works great there.

I can’t really say, I bought it for the epilator as I have a Clarisonic for the brush part. The brush is removable but I think you have to replace it with a Braun brush

You can certainly do that. But only at your own risk! It is a battery-operated device. The consequences for people and the device are therefore manageable. However, according to my assessment of the device's construction, it should not be used.

We were able to find the item in our online shop with the item number 5671388 mentioned by Mr Frei: Braun Face epilator head for Braun Face 810 (shaving head)

Yes, it is available. You can find the spare part with the item number 5671388 or as an accessory with the Braun Face 810.