Hi Marci!
October is a great time to visit! The weather is slightly milder and the crowds are lighter.
I would definitely go with either the Quick Service Dining or the Standard Dining Plan. Deluxe Dining is an abundance of food, and if your son doesn't each much, I wouldn't choose that plan.
Quick Service is sort of "check in/check out." I have a 2-year old who is also a picky eater, and it made it easier to take off if and when they get too fussy, versus a table service, where you have to wait for the waiter, check, etc.
That being said, the table services at Disney are delicious. So if you'd like to get treated here or there, I'd get the Standard Dining Plan, which gives you 1 table service per person per day.
Also, there are a number of table services without the characters. When you make reservations, Disney usually classifies which restaurants have characters and which don't. My son was afraid of characters such as Tigger, but had no problem with the human characters, like the Princesses (smile).
For further details, click below:
Quick Service Dining
Standard Dining
Good luck and have a great time!