There is a lot to be said here but I will restrain myself.
For only charcoal filtration, any faucet should work. Use a charcoal filter that is standard size (guessing without moving my keister to measure that standard means 3 inches in diameter by about 10 inches long.) Pressure drop should be modest until depleted so flow would be high.
With R.O. water, one needs a pressure tank and at least 3/8 poly tubing to use with a standard faucet. One may also need other active components to keep the pressure up. My R.O. system feeds a Brizo Venuto, a Brizo pot filler, a plant wand, a refrigerator ice maker, and eventually a bar sink faucet. However, I have a peristaltic brine-driven pump from Spectrapure, and two pressure tanks.
With R.O. filtration, it is possible in some cases for the resulting water to become soft and acidic, and this can leach lead where present. For such cases, a lead free faucet is needed. My R.O. input is municipal water that has been dosed at the source with alkali chemicals, and pH measurements show that it is still alkaline after R.O. filtration.
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