Hi. Southwest doesn't assign seats, just a group letter for boarding. They have groups A, B and C. But, there is also a preboarding group - those that have disabilites and those travelling with children under the age of 5. So if you fall into one of those categories, you board before everyone else. You can also save seats for anyone in your party that can't board with you at that time.
We just stayed at the Polynesian and didn't even bother printing boarding passes the night before we left for home. When we got to MCO we did curbside check-in and they gave us our boarding passes. Lo and behold, we were group A, which I didn't expect (nor did I need per se, b/c we have a 3 year old and a 1 year old). So don't worry about the resort having to print that out for you. Based on our experience, I would say you have nothing to worry about!