Can this be hooked up to a refrigerator water dispenser?

possibly, would be about connected the sizes.

Possibly. There is a tendancy for Ice Makers to run too little water since the pressure tends to be much lower from this tank, so in turn the Ice Maker only fills so much, often with some models, short cycling where it dumps semi-frozen cubes and smaller quantities. This can cause Ice Maker Issues too. Other issues I've seen (as I have worked on a lot of other people's Ice Makers for my work) is the water runs into the Ice Maker tray too slowly from the water tube, which in turn allows it to freeze over time completely blocking the flow. Now I did manage to get mine hooked up. Though, I would say it would be good to see if you can adjust the Ice Maker level and make sure the pressure is good before hooking it up. If you end up using the RO Faucet regularly or to points of running to no pressure, then you can quickly find you facing issues with the Ice Maker. If it's dedicated to the Refrigerator, then you could face less issues. Possibly getting a larger tank than the one provided can prevent issues rising. If you know what you're doing and know when to limit drawing your tank dry just for drinking water, and having the system as close the fridge as possible to keep the pressure up, then it can work great with just this setup.

Yes, this could be hooked up to a refrigerator water dispenser.