Looks like these ones: https://en.wikipedia.org/wiki/Oak_processionary

Could they be line processionary caterpillars? If so, their hairs can cause severe issues (including blindness).

I typically avoid caterpillars in the wild, especially hairy ones.

You can contact your local health/environmental agency and request an ID from a professional. Where I live it normally takes a day or two and they can confirm if it poses any danger.

Caterpillars?

Looks like a regular caterpillar orgy to me.

Not really

I don't know but I don't want to get involved.