In Ultra Sun the list of Totem Pokemons you encouter are as follows
Their respective types are
From you can see above the Totem Pokemon theirtypes and Level.
The Alolan League
-Excellent base Atk stat
-Reliable Def and SpD stat
-Gets good moves
-Excellent Atk stat
-Good SpA and SpD
-Fatser than Incineroar
-Pretty low Def stat
-Less base HP than Incineroar
From the above information we can conlude that Incineroar is the best as it almost covers all the types which we will face through the game and theother are covered with the moves it learn.
So we will go with Incineroar.
[email protected] Z
-Fighting move(Double Kick,Brick Break,Low Sweep)
Flare Blitz for STAB and has a very good Atk stat.
Drakest Lariat for STAB as well as Z move.
Earthquake for higher type coverage.
Fighting mob=ves give even more coverage also aginst Inci's weakness rock.
You can use flame charge if you want to be fast.
Also Thunder Punch is great coverage and physical to hit those Water type out
Using the above moveset you can counter every Totem Pokemon and the Elite four,your rival,The Champion
Hope I Helped