Looks like it's not all-inclusive, they rejected four of my options when I applied a few years back but none are on the list.
Iowa may have updated their process since I moved away, but Indiana (where I live now) has a much better system than my past experience in Iowa - the agent at the Indiana DMV inputs your desired plate in real-time and confirms with you sitting there if the plate is available/spelling etc. No submitting various options on a form to a black box to have them all denied for no reason, you can explain to a real human the meaning if something might look weird. Only downside is that Indiana doesn't offer Iowa State plates...