I think selecting pokemon here is too arbitrary. I would change it to "Megahorn, hitting anything hard that doesn't resist it".
I would leave that out. Leftovers is the standard item in GSC.
I would restructure the rest of the analysis.
Why does Starmie checking Machamp and Nidoking make it a good partner for Heracross as the latter already deals with them well as you said?
I would combine the explanation for Rest and Sleep Talk and mention that it makes Heracross one of the best checks for Nidoking (assuming it lacks a fire move which is usually the case), you can also list Tyranitar here if you want. I'd add that either of these three (Nido, Tar, Champ) could carry Fire Blast which changes the matchup (from dominant to unclear). Curse allows you to sometimes overcome Zapdos against which you can't make progress with just Seismic Toss, so listing Zapdos as target for Seismic Toss is misleading to me. You can also state that Curse is the better move against other Heracross (Curse Hera beats S-Toss Hera) as well as giving you better odds in fighting CurseLax.
Snorlax is used on all teams but you should talk about what kind of sets it can use on teams with Heracross. Body Slam, Earthquake, Curse and Self-Destruct is a common choice, especially with Curse Heracross, as often Skarmory is the only counter for that set on stall teams so you can lure it in and take it out. Seismic Toss Hera can overcome Skarmory as it gets 4HKO'ed if it switches in asleep after Rest without having burned any sleep turns, so a lure for it is less necessary (but still a good option regardless).
Raikou makes a good partner for Heracross (walls Zapdos while Hera can switch into ground attacks).
