Can be one Oyster or contactless card used by 2 or more people ?
Can be one Oyster card or contactless bank card used to travel in London by 2 or more people ?
No. Only one person can use Oyster card or Contactless bank card to travel by London tube. If you have both Oyster card and Contactless card, then each of them can be used by 1 person.
The rule is: Two people can't use the same Oyster card or Contactless card for a journey.