To add, the hopper can indeed leap when it's a king. I used it because it was so cute and to be honest, it's only really useful for the leaping as king. It did get me out of some predicaments so it's not completely useless! The debuff seems to only lower the resistances, so it's not that useful..
I beat rank S the second time with a team of: Hopper as king Bazoo beetle Bombsnail Spotted beetle, the only one I see as absolutely necessary. Butterfly
I dont know the exact names, but they were all lvl 5 and rank 8, so not even max level. Most of them had around 650 to 750 hp, with 100 attack and 90 defence on average. Also pretty much 100 resistances, although some had around 80 explosion.
how I won, was keeping almost all my insectors on the back rank. When you do this, the enemies keep their king around their own side. If you go forward, the king gets involved and against dark emperors this is deadly due to their 2 range special. Just stay back, kill the escorts, and then it's 5 on 1 if you maximize the heals.
The butterfly is more useful than you think to blow someone back. If you hit the special, they get blown all the way back to their end of the board. You can blow them off if theyre on the edge, but its just useful enough like this to make it a 5 on 3 (if their king doesnt get involved).
Other insectors that are very good IMO: Hercules beetle. Their special attack is basically a great Aoe if theyre in a row (which they often are) and it can push insectors off, so it's a double special. Usually these also have high health to begin with.
Silkspiders. From what I could see, all insectors except the spider itself have lower accuracy when on the web, so you can use this defensively as well.