Right.
Your 'Mence.
I know you have an identical DDmence.
Use that as Adamant prefers Defensive moves and DD is categorised as one.
No other changes.
Starmie.
Clone it then give the clone Recover and use the clone, or it will just keep being incapable.
Metagross
No offence meant, but as it is rash it likes to support, so don't use in the Palace.
Latios is fine, it will mainly attack and occasionally use CM.
That is my rate, a little higgeldy-piggeldy, but hopefully understandable with a clear explanation.
My team, if you want it, was:
;282;@ Lum Berry (Crobat of PM knows toxic)
Trace
Modest
WoW
CM
Psychic
T-bolt.
At least 1 of each category move, so cannot be incapable.
;260; @ Shell bell
Brave
Curse
Surf
IB
EQ
Worked wonders.
;376;@ lefties
Iron Def.
EQ
Meteor Mash
Explosion.
If possible, against the Maven's Slaking, use Latios.
Levitate, Psychic-type and Lum will defend against its EQ, Brick Break and Swagger.
Hope that helps.