Frenchies and Golden Retrievers are quite different breeds but I definitely think you have made the right choice. Please get absolutely gold-plated insurance, the highest you can get. Goldens have numerous health problems which can be expensive to treat, including cancers, eye issues, joint and ligament issues, dietary allergies... the list goes on. In addition to the tests already recommended, I'd want to know that at least one parent was ICT-A trait free. It's a skin disease.
Wherever you are, use the actual official registry for pedigree dogs and don't take it on trust that the tests the breeder says have been done, have been done. Nor that the puppies you're buying are from the actual bitch/ dog you think they are. I'd definitely choose a well-known kennel affix, rather than a home breeder.
Goldens are epic and I would never have another type of dog. However, they need quite a lot of vigorous exercise - ideally about 1h 30 a day of off-lead running, sniffing, and preferably some sort of brain work. Lead walks absolutely will not cut it, you will end up with a dog who is chewing furniture, stealing underwear, and demand barking. They also need a lot of human company typically, although mine is a bit of an outlier on that front and is fine for a good few hours alone.
As to their relationship with cats, goldens are generally very gentle and mine would run away from an aggressive or defensive cat, in sheer panic, with tail between legs. We don't have one at home; she is interested when she sees one or visits homes with one, but tends to flatten and stay well away. Introducing when the dog is a young puppy will be fine. Cats can defend themselves, they have sharp claws. Smaller furries, I would not trust them (or any dog) with, really.
People assume that GRs don't have much prey drive or chase instinct. In my experience this is absolutely not true. Mine LOVES a chase, as do others in her line. Her sibling killed and dismembered a squirrel. She has brought me dead birds and small mammals - they are bred to do this.