I think it is okay to mix two different metal finishes, but if you add a third, then that is over the top.

I have designed wall sconces and chandeliers that used both nickel and gold finishes together.

Gold can be gaudy or garish, and so it should be used with restraint. Too much gold will make a room look cheap - or like Las Vegas.

If you tire of gold handles, they can easily be changed.

I’d keep the kitchen consistent. Play with the bathroom as it’s a unique to itself room. You can have the inside hardware the gold and the outside door hardware the same as other visible hardware.

Mixing metals is a room by room decision. Satin nickel lighting in a kitchen suggests ( to me ) you have a spec build - pick one from column a one b etc. ?

Show what you've chosen, what look you are after. Yes you can mix, but the what and where matters : )

I need to see the choices already made so post pics here in a comment . DO NOT start another pst. I happen to like chrome in bathrooms and usually stainless for faucets and pulls in kitchens I think the gold trend will be exactly that a trend that will be OUT before long.