One option is to have a Decidueye (if you started with Rowlet). It's a strong Grass / Ghost type. Along with a Raichu for Electric - type power. And a Sandslash for its Ground - type moves. This combination can cover a lot of different type match - ups you'll come across in the story.
A good party could be Rowlet as your starter for its Grass typing which is useful in many early battles. Then, Pikachu which is always a reliable Electric - type. And Mudbray for its Ground typing which gives an edge against Electric and Fire types. This combination can handle a variety of opponents you'll face during the story.
You can't go wrong with a team of Pikachu, Eevee, Charmander, Squirtle, Bulbasaur, and Pidgey. Pikachu is iconic and has electric - type moves. Eevee can evolve into different useful forms. Charmander is a classic fire - type starter. Squirtle for water - type attacks. Bulbasaur for grass - type moves and Pidgey for early - game flying support.
In my opinion, Zacian is a must - have for the story in Pokemon Sword. It's a very powerful Legendary Pokemon. Along with Zamazenta, they are key to the story. Also, Eevee can be a great addition. You can evolve it into different types depending on your needs during the story. And don't forget about Pikachu. It's a classic and can hold its own in story battles with its electric - type moves.
Charizard is also very suitable. It's a powerful and majestic Pokemon. In a story on Pokemon Island, it could be the protector of a certain area, using its fire breath to fend off threats. And its evolution journey from Charmander can also be incorporated into the story for more depth.
I recommend Torracat (evolved from Litten), Brionne (from Popplio), Dartrix (from Rowlet). Torracat is strong and has good fire - type moves. Brionne is cute and can hold its own in battles. Dartrix has some nice grass - type attacks. Also, having an Alolan Sandslash for its ice - type moves and a Lycanroc for its speed can be great additions to the team.
The story of Pokemon Sun and Moon is of moderate length. It depends on how quickly you progress and how much you explore.
The length of the story in Pokemon Sun and Moon is not fixed. It usually takes players anywhere from 20 to 40 hours to complete, depending on their playstyle and how much they get involved in side activities and catching all the Pokemon.
In Pokemon Sun New Story, it may introduce new character arcs. For example, a new villain might emerge with a unique plan that threatens the peace of the Alola region. The protagonist would then have to go on a quest to stop this villain, all while evolving their Pokemon and making new friends along the way. There could also be new types of Pokemon contests or challenges specific to this new story.
The story length of Pokemon Sun and Moon can vary depending on how much time you spend exploring and doing side quests. But on average, it can take around 20-30 hours to complete the main storyline.
The new story in Pokemon Ultra Sun can bring a fresh perspective to the Pokemon world. It might introduce new friendships between characters. There could be a new tournament or competition added to the plot. Also, the story may have elements that connect the Alola region more closely to other Pokemon regions, like through some ancient artifacts or a traveling trainer from another place who brings new challenges and knowledge to the Alola region.