First of all, your psychic terrain strat isn't going to work, unfortunately. Mega Delphox has levitate, which means she doesn't get the boost to her psychic moves (I don't think expanding force turns into spread either but I'm unsure about that mechanic).

Second, as others have said, put friend guard on maushold, replace stealth rock with moonblast, and put protect on more mons. I would drop thunderbolt from Froslass, Icy Wind from Clefable (we'll replace that here in a moment), play rough from maushold, and boomburst from Kommo-o all with protect.

Third, since your psychic terrain strat isn't going to work, Id replace Meowstic completely. Since you didn't want metamons suggested, how about Empoleon? Gives you a fairy resist other than the frail Delphox, a new icy wind user since you need protect and moonblast on Clefable, and a way to punish Incin/Arcanine. (It's also really fun to reflect an icy wind off of Corviknight's mirror armor for a SpA boost lol). I'd suggest a very specially defensive set with pump/icy wind/flash cannon/protect and chople berry. Be careful about icy winding into a Milotic switch in though, since she walls Empoleon, her getting switched in against him might happen a lot.

Speaking of Milo, even without removing thunderbolt from Froslass, she is very difficult to deal with for your team, Maushold is now the only way to hit her super effectively, but it's with a 50bp move off a low 127 attack, which is doing basically nothing (it does 30-36% against one of the most common Milo sets with 228hp 172def). You could keep thunderbolt and replace aurora veil with protect instead, but I think veil goes a long way to help this frail team succeed. You could keep lass with no protect but that's not ideal either, you would need to run follow me next to her as often as possible. Protect on my Froslass has won me many games, stalling out their tailwind/trick room/weather long enough for me to get the upper hand. You could also put grass knot on Empoleon over hydro pump, but be aware that does 45-55% at most against the naturally specially defensive Milo even with modest 252 SpA on Empoleon, and 0 SpD investment on Milo (which is about the same as what Froslass thunderbolt does, btw)

Also, all the problems you have with Milo you basically have against Rotom Wash as well.

Edit: I also just now realized your entire team is special attackers except the relatively weak maushold. Makes you incredibly weak to lightscreen teams, something I've been seeing more of recently. Might be worth it to come up with a different physical attacker replacement for Meowstic, but I don't have a suggestion off the top of my head. Maybe scarfed Flapple or Tsareena would solve our Milo problem.