So, first, let's focus on the Elite Four:
Hala
Type specialized in: Fighting
Total Pokemon types: Fighting, Normal, Water, Ice
Alolan Dugrio: Normal type is not very effective on Alolan Dugtrio, but Hala's Fighting and Water-Fighting types will do twice the damage.
Mudsdale: Normal and Fighting type do normal damage to Mudsdale, but Hala's Water and Ice type moves are super effective.
Olivia
Type specialized in: Rock
Total Pokemon types: Rock, Water, Fairy, Electric, Steel
Alolan Dugtrio: Electric type has no effect against this Pokemon, Fairy, Steel, and Rock are not very effective, but Water type is super effective.
Ok, now I'm just going to do pros and cons
Mudsdale:
Pros:
- Electric type has no effect
- Rock type is not very effective
Cons:
- Water type is super effective
Acerola
Type specialized in: Ghost
Total Pokemon types: Ghost, Dark, Flying, Grass, Ice, Ground
Alolan Dugtrio:
Pros:
- Flying type is not very effective
Cons:
- Ground type is super effective
Mudsdale:
Pros:
A lot of these types hit normal against Mudsdale
Cons:
- Ice type is super effective
- Grass type is super effective
Kahili
Type specialized in: Flying
Total Pokemon Types: Flying, Steel, Poison, Fire, Dark, Normal
Alolan Dugtrio:
Pros:
- Poison type has no effect
- Flying type is not very effective
- Steel type is not very effective
- Normal type is not very effective
Cons:
- Fire type is super effective
Mudsdale:
Pros:
- Poison type is not very effective
Kukui
Type specialized in: None
Total Pokemon types: Rock, Ice, Fairy, Normal, Flying, Electric, Steel, Normal, depends on which starter you picked
Pokemon: Lycanroc, Ninetales, Braviary, Magnezone, Snorlax, Decidueye (If you picked Popplio), Primarina (If you picked Litten), Incineroar (If you picked Rowlet)
Alolan Dugtrio
Pros:
- both Ground and Steel (which are alolan Dugtrio's types) are super effective against his Lycanroc
- Steel type is super effective against his Alolan Ninetales
- Ground type is super effective against his Magnezone
- (if you picked Rowlet) Ground type is super effective against his Incineroar
Cons:
- Ground type has no effect on his Braviary
- Steel type is not very effective on his Magnezone
- (if you picked Popplio) Ground type is not very effective against his Decidueye
- (if you picked Rowlet) Steel type is not very effective against his Incineroar
Mudsdale:
Pros:
- Ground type is super effective against his Lycanroc
- Ground type is super effective against his Magnezone
- (if you picked Rowlet) Ground type is super effective against his Incineroar
Cons
- Ground type has no effect on his Bravairy
- (if you picked Popplio) Ground type is not very effective against his Decidueye
That's a lot to take in at once, even for me, and I wrote it! All in all, I would pick Alolan Dugtrio, but it's your choice! After all, it's your Pokemon.
Oh, and if you want to know more:
http://www.serebii.net/sunmoon/elitefour.shtml
http://pokemondb.net/pokedex/mudsdale
https://pokemondb.net/pokedex/dugtrio
I hope this helped! :)
