When I ordered my cabinets they were sold as zebrawood. They were delivered and they are a laminate. So much for wood cabinets. Donna

I would get some in real life and test them out in person once the cabinets are painted--you can stick them on to see how they look before drilling. We have pulls very similar to Ascendra in our kitchen and I like them a lot, but it just depends on the style you're going for. We opted not to use knobs and just have pulls on both doors and drawers--3.5" ctc throughout. Some people like to vary the sizes based on the drawer sizes, but with your vanity I don't think I would. Our new bathroom vanity came with hardware that is 5.25" ctc on tiny drawers. I didn't love the size initially--we didn't get to choose it since it came pre-drilled--but it's growing on me.

"That sounds like a code violation to me." Although I'd argue it's not a best practice, I don't find anything in the 2018 IRC which precludes the use of cabinet toe kicks as plenums for heating and air conditioning. The IRC specifies a maximum flame spread index of 200 for duct materials. The flame spreads of wood species used for cabinet construction are well below that. The ignition temperature of wood is also much greater than the 125F to 130F +/- temperature of supply air from a gas-fired furnace. The melting point of body lotions is designed to be at or less than body temperature and the temperature of the cabinet bottom could easily be above that if the OP has a gas-fired furnace. My concern is the potential for mold/mildew to feed on wood and any organic materials that might accumulate in the space when the system is in air conditioning mode.

Custom would typically imply locally sourced from a millwork shop or local cabinet builder.