You will need to hire somebody (a designer) to sort out all you need to buy online. So you either pay that person and they give you all the links, or you pay the premium at a showroom and hopefully the staff is knowledgeable enough to help you. Unless you have done at least 5 bathrooms, it is very hard to figure out what you are doing.
I rely on Kohler a lot, it has never disappointed me or my clients, but there are wonderful companies out there, one of them I recently used, is Graff, fantastic fixtures at great prices.

Thank you Aggie! I appreciate your advice. We like the look of Kohler too.