If you are not sure about the tone of the colour, you can order colour samples and compare with your taps at home before you buy. In case you'll still be needing for brushed gold waste plugs, you can have a look at Fontaine Industries. We have waste plugs in all kinds of colours and finishes at great prices.

I would change the island and side bench tops to white. The side bench in black will be absorbing a lot of light from that window. If you keep black at back go black tap, otherwise if ditching all black benchtop did ditch the black tap idea and handles

An undermount stainless steel sink will match well with your brushed gold tap and white benchtop. Although different in colour, the sink and tap shared same kind of texture so It won't be distracting. Colour wise, the sink will match perfectly with your white benchtop. We got some photos of our customers who have used the same kind of design before, check out the link below if you would like to have a look. https://fontaineind.com.au/colette-kitchen-laundry-tap-mixer-brushed-gold https://fontaineind.com.au/ariella-kitchenlaundry-mixer-tap-brushed-gold

The pros can be that brushed brass finish is pretty versatile, it can match with many different styles no matter it's contemporary or classic. The gold colour can also add a bit of warmth and elegance to the kitchen. The cons can be that it is not easy to find brass taps, handles and other accessories without colour difference for different brands or ranges. So I think it's better to stick with the brand you have chosen and confirm the tone of brass before you buy. You can also have a look at our brushed gold tapware and matching accessories, there are some example customer project photos for your reference.