All these movesets are good, but they're forgetting one tiny detail... Milotic's weakness to Electric-Types.
Here's my Milotic:
Ability: Marvel Scale
Item: @Flame Orb
Scald (STAB, May cause burn, Great accuracy, Coverage against Fire-Types, Rock-Types, and Ground-Types)
Ice Beam (Powerful move, Great accuracy, Coverage against Grass-Types, Dragon-Types, Flying-Types, and Ground-Types)
Bulldoze (Great accuracy, Lowers target Pokémon's speed, Coverage against Electric-Types, Fire-Types, Rock-Types, and Poison-Types)
Facade (Assists ability, Doubles in power due to burn, Great accuracy)
Overall, this is a pretty good moveset and would be strong in any battle whether it's a single, double, triple, or rotation battle.