Will "hiding" contacts on Google Contacts affect other apps' behavior?
The name of the caller will not be identified if the contact is hidden in Google Contacts.

The contact will be removed from the contacts list in the stock Samsung contacts app.

I tested this by calling my mobile with my work phone. I hid my work phone number in contacts.gooogle.com, and I also had to remove the number from my personal information in my Samsung Account, as well as my Samsung Account in my secure folder.