you have a good start here. I will be watching for pics of the completed set up. I cannot personally give you advice on the Cardina family as I too am just now beginning.
If you can swing $200 or so for an RO unit give it some thought. I got mine from Buckeye Field Supply. Very helpful people. If I remember correctly I have dealt with Russ. He also is an aquarist. If you go this route your local water does not matter, just remineralize to your nessessary values with a remineralize product of your choosing. Plus it is so much tastier for you to drink than the chlorinated junk from the tap.