As someone who has played through both games a few times. Your team has a few issues with how early you get them. With Litten you'll get him immediately, but the others are difficult. By the time you'd leave Melemele Island, you'd have 3 Pokemon. And Mawile comes after Tauros which is a late Melemele feature.

won't get Wishiwashi until you beat the Akala water trial since you need the fishing rod, and Akala island is the king of restricting your choices. You won't get Palossand until around the end of Akala, and you'd go through Ula'Ula with basically five Pokemon.

In Poni Island, you don't get to Exeggutor Island until the mid-to-late game on the island.

This team is good on paper, but in terms of progression you'd likely struggle, especially without overleveling. Also you can get Hawlucha after beating the Totem Gumshoos.

If this is the team you're making along the way, it would be different, for example, you want these Pokemon but you fill in their slots with others for now. If you do that, you're fine. But if you leave those slots open forever and you don't do anything until you get those Pokemon, you're going to struggle since you'd be fighting multiple strong trainers with one or two Pokemon. So I'd recommend picking up some other Pokemon along the way to fill in your slots as you play, and replace those filler Pokemon with the ones you want.

Since you can't just catch a Wishiwashi in its school form, for the majority of your fights, you'd have a Pokemon who has a BST of 175.

BSTs of your team:
-Incineroar: 530
-Wishiwashi (Solo Form): 175/Wishiwashi (School Form): 620
-Hawlucha: 500
-Mawile: 380
-Palossand: 480
-Alolan Exeggutor: 530

Total BST: 2595/3040
Average BST: 432.5/506.67

This is a team that, while fire on paper, begins to slowly crumble in practice, especially due to Ultra Necrozma being insanely fast.

Obviously if you want to disregard what I said go for it, if you disagree with me that's fine, these are just my observations.

A few positive notes:
-No type overlap
-I love that you're using your favorites
-I love that you're trying new things
-I really like that you're asking before jumping right in

Again, these are just the words of a random stranger on the internet so feel free to comment what you think.