Would using seafood stock instead of chicken broth/stock work in a butternut squash soup? I'm trying to make a butternut squash bisque, specifically, which by its least-strict definition involves a seafood stock/broth.

All the recipes I've found are for butternut squash soup, which is not as fun to make or talk about.

My concern is that the fishiness of the seafood broth/stock will overpower the butternuttiness, or make it taste flat-out disgusting.

I'm using Chef John's recipe for this.

Any input is appreciated. Thanks!
TL; DR

As long as you get the balance right anything that's tasty separately can be mixed together and still be tasty.

What I would do is to make the butternut squash soup first without any stock, set aside one bowl of said soup and then little by little add the shrimp/lobster stock into the kettle until just right to your taste-buds.  Then add the separate bowl back into the kettle.

Why? Your taste-buds will have gotten gradually used to the shrimp/lobster stock and the final product will be slightly over the top, so adding the bowl back in will make it just right for your guests.