If I attacked with a Rapid Strike Pokemon last turn, then use Ninja Boy to swap it with Zeraora V, would the Zeraora V's "Cross Fist" attack do damage to a Benched Pokemon?
No, all effects carry over, so it would be considered the same Pokemon.
Source: TPCi Rules Team (2021-07-01)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH6_53
SWSH6_53
XY11_103