Great news Reid, I hope you manage to get booked up.
As you know I have been in the last two weeks in July and was pleasantly surprised by the lines (provided you were in the park first thing). There were no different to when we had visited in February either walk on or 20 minutes. The weather is very hot and humid but we liked it. We have booked to go back at the same time.
I would imagine October to be not as busy as in the peak summer season but it still will be busy. I don't think Orlando ever really has a quiet time just a slightly quieter time if you know what I mean.
I can recommend February school holidays as being a good time to go. The only drawback is coming back to our winter weather after two weeks in the sun. However, in answer to your question I would pick October primarily because it isn't peak summer season and with it being your first visit you will want to do all of the rides in each of the parks which I think you will have a better chance in doing at this time of the year.
As we have been before we didn't feel the need to do every single ride in July, we just did the new ones and the favourites. When we went for the first time we did every single ride.
Avoid Easter because that is supposed to be even busier than the summer season from what I have read.
Ideally avoid all school holidays if you can but be aware that off peak times are popular too. The hotel I wanted to go back to was booked up from 13th June to 15th July 11 months in advance, so we had to book for 15th instead of 1st July as planned.
Also if you go in October you can save up even more money to spend over there or even start saving up for your next Orlando holiday because, unfortunately, Orlando isn't an once in a lifetime experience. Once you have been you will want to go back again, that is a promise.
