Hi Janelle,
October is a gorgeous month to visit Walt Disney World. The heat and humidity of the summer is typically gone and the weather is usually pleasant and comfortable with daytime temperatures in the mid eighties and lows around 70-75. The average monthly rainfall is around 2.73 inches.
We have visited a number of times in mid to late October and find the crowds low to moderate. The only exception we found was on the weekends at Epcot, when often the crowds increased with local guests arriving to enjoy the Food and Wine Festival. I like to use
www.touringplans.com to help judge the expected crowds during our visit. The site uses information like past crowd levels, special events and holidays to rate each day of the year with a number from 1 to 10. Ten is the highest crowd levels and longest waits and one is of course the lowest. During the week you mentioned, the crowds are rated at four for the majority of the week, an eight on the day you arrive and a seven on the 19th. Given this information, and our past personal experience, you should find the crowds very manageable.
As for the dining, the character meals, to my knowledge, have always been at least one table service credit. The quick service credits that you mentioned have always been used for counter service meals and not character dining. If you were able to use one for a character meal in the past, that was a little Disney magic, but unfortunately not the usual case.
Hope you have an amazing time!