CS Restaurants in WDW... when do they close?

[discnewbie]

How do I find out, ahead of time, when the CS restaurants in the parks close? I've heard that sometimes they close early. Specifically, I am curious about Cosmic Ray's in MK, Flame Tree BBQ and Yak and Yeti in AK, and Sunshine Seasons in Epcot. I've also heard Pizza Planet in HS closes earlier than its posted time, sometimes -- is this true for peak times (March)? I can't seem to find this information anywhere and I'd like to be able to sort of plan so I know if we can stay later on in the parks after dinner, or not.

Thanks!

Edited to add: found a few of the restaurant's hours that I asked questions about, but the others say the hours "varies".