I battle my brother regularly and I've always wondered how these moves work. because your Pokemon never crit with the hearts or dodge or shrug off poison in these battles, so are they full power, or normal power (how they would be in a overworld battle)?
You're confusing Affection and Friendship, they're two different mechanics in Gen 7. Affection boosts don't transfer into online battles, as they're just too good to be allowed. Friendship levels boost the power of Return and Frustration, not Affection.
Hope I helped!