Stone Edge is another option to hitting Volcarano but you shouldn't be staying in on Volcorana anyway
Unless Volc is running LO + Fire Blast (the majority of them don't), it can't OHKO Mamoswine unboosted. If you're running a focus sash, it can't OHKO, ever. Volc is an extremely dangerous threat to so many teams; letting it set up is often a serious error. A better argument here would be that EQ is usually sufficient to take Volcarona out. IIRC, LO Mamo OHKOes offensive variants. EQ should be enough after SR whatever spread Volc is running. Don't make blanket statements about what should be staying in on what. Also, could you move this to OO or add a mention of Stone Edge on the LO set. It's a much better option on that set.
Otherwise, I'd say this looks fine.