Fighting and Flagrant

[The_Rookie]

In order to classify an act as fighting do you need at least 2 participants?

For example, we know that kicking an opponent is considered an act of fighting. But what if A1 kicks B1 after both go to floor for loose ball and B1 does not react in anyway...
Is this just considered a Flagrant Foul because of the kick and not classified as fighting?

How does this impact the throw in location?

NFHS rule set.

Thanks!