ice maker and dishwasher supply line preference

I would use 1/4" copper (L) for the fridge with compression fittings with a regular shut off valve not saddle valve. Don't forget to make a loop behind the fridge so you can install the line and roll the fridge back in place or pull it out for cleaning and service. For the dishwasher I would use braided stainless, the reason for the braided stainless is flexibility when installing or moving out for service, it's pretty tight under there.