OK, other than many of the team members needing to be changed, i'll recommend set changes first.
Use a spread of 240 HP / 212 SpD / 56 Spe with a careful nature on Gallade, leftovers over big root, and knock off over poison jab.
That Delphox set is really bad i'm afraid. While there's nothing wrong with CM delphox, the moveset should look like this:
Delphox @ Life Orb
Ability: Blaze
EVs: 252 Spd / 252 SAtk / 4 HP
Timid Nature
- Calm Mind
- Grass Knot
- Fire Blast/Flamethrower
- Psyshock/Psychic
You could run leftovers over life orb, but this is the set you should be running.
As for Gardevoir, you should either drop CM and go offensive (you don't need two CM users), or drop delphox. As for the set, this is what should be used.
Gardevoir @ Gardevoirite
Ability: Trace
EVs: 24 Def / 232 SpA / 252 Spe
Timid Nature
- Hyper Voice
- Psyshock
- Focus Blast
- Taunt/Shadow Ball/Will-O-Wisp
If you want to keep using it as a calm mind, use the exact same EVs and natures with a moveset of Hyper Voice, Psyshock, Calm Mind, and Taunt/Shadow Ball
I honestly don't think this set, or musharna in general, will fit on this team. That set serves as nothing more than a gimmick. I recommend changing it with a pokemon from a list I will provide at the end.
Alakazam should have a spread of 252 SpA/ 4 SpD/ 252 Spe, should have the ability magic guard, should have focus sash with a set of psyshock, focus blast, hidden power ice, and shadow ball
If you want a magic bounce user, you should probably be using espeon.
Espeon @ Leftovers
Ability: Magic Bounce
EVs: 252 Spd / 252 SAtk / 4 HP
Timid Nature
- Psyshock
- Dazzling Gleam
- Shadow Ball
- Morning Sun
Some things about the team: it's WAY to specially biased, and many of the pokemon have better options. I'll give you some pokemon that you should consider on the team.
Starmie: Honestly I don't like the idea of espeon as a means of dealing with hazards, and starmie is a much better way of doing it, and provides more than enough offensive pressure.
Mew: With the ability to run all kinds of sets to aid your team, it could easily be added as a defog user to get rid of hazards.
Victini: I would definitely recommend victini, as it could help the team with its lack of physical attackers and fire off insanely powerful V-creates
Jirachi: although not as good as it used to be, it could also help with with the physical bias.
Deoxys-S: would be an excellent late game cleaner or hazard setter
Deoxys-D: Same as S, but only as a hazard setter
Lati@s: could also be used as a means of hazard removal as well, and as a potent special attacker
Medicham: could be used as an alternative to gallade, making mono-dark easier to handle (although still hard).
Slowbro: a good defensive psychic.
you should consider replacing musharna, delphox, and you magic bounce user with one of these.