It’s definitely possible to change out the hinges without redoing the cabinets – you would just have to make sure that the holes on the frames where the old hinges were, are able to be filled and touched up so that they’re not obvious. I’m not sure of the cost, but hinges aren’t cheap, and I definitely recommend using a carpenter to do the work. Hinges can be maddening!
Let’s talk first about metals. As a general rule, I like to keep the different metals in a kitchen to no more than two. If you have stainless steel appliances, that counts as one metal. So that leaves one other metal you can bring into a kitchen. If you’ve got brass light fixtures, that’s your one other metal. Your new hardware should be nickel or brass.