The only full service restaurant that has outside dining is the R&C. But there are several counter service locations where you can sit outside.
Cantina de San Angel, Biergarten, Tangerine Cafe, Liberty Inn, Electric Umbrella
I've been there in the spring/summer and Alfredo's has had limited outside seating. You have to request it and it may be a long wait. You would not get a good view of Illuminations from that location, but it would be nice to be outside on a cool Florida evening (all the rest of the time I'll stick with the A/C).
BTW, watching Illuminations from the R&C is great, try the scotch sampler.
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