Hello! Do you think I could substitute Butter nut Squash for the Sweet Potatoes?

Excited to make this! If I make it the weekend before Thanksgiving, should I do the boiling step and refrigerate, just refrigerate, or boil and freeze? It seems counterintuitive to boil before freezing but I'm not a gnocchi expert :)

And/or buttercup or kabocha squash for even more flavor.
Yes, cook the moisture out of it.

Absolutely! Just remove as much excess moisture as you can.

Yes. Here's a recipe from Lidia Bastianich to guide you. https://www.bonappetit.com/recipe/butternut-squash-gnocchi-with-sage-brown-butter