I agree that the correct response is #2 -- preventative officiating.
I also agree that, by rule, this is a foul for not having at least four players on each side of the kicker at the kick. Even if the rule stated "no more than six", you'd have the same issue since they're spread 7-K-3.
The intent of the rule is to spread out players to not overload one side of the field -- but it's meant to spread out R as well as K. Ad absurdum -- if K is trying to kick off with 9 players and spreads out 6-K-2, R is going to overload to the 6 side of the field, increasing blocks/collisions/etc. there. In that situation, the intent of the rule is still violated, even if "no more than six" still held.
It's an easy enough fix that, if the holder doesn't count, K still has to line up 5-K(holder)-4.