I've had a maximum of 9 tanks up at one time and have not had any anemones for any of my clown pairs and they do just fine. A popular misconception in this hobby about clowns and nems.
Based on what you say the store is telling you i would definitely find another store, even if it means a little bit of a further drive. I personally will drive an hour for the good stores and to ensure i am dealing with people who know the hobby and won't steer me wrong. As mentioned above, there are usually a ton of people on this forum that will be more than happy to answer any questions you may have. The good thing about the forum is no one is out to make money from you so there is no conflict of interest as there seems to be with your current shop.
For a new tank i would be testing salinity, ammonia, nitrites and nitrates regularly. Once you acquire some corals you may have to test for a few other things but i wouldnt worry about them right now.