As I've seen previous projects with the Raspberry Pi being enclosed in stuffed animals and plushies. I've wanted to attempt a project in a similar environment. Will there be a problem with overheating the device when it's enclosed in such a tight location? My Raspberry Pi is already in a Geaux Robot case, so there's that to be considered.
The RPi is unlikely to be a problem. However if you insulate it well enough it will of course overheat eventually.
There will be a temperature gradient from the RPi to the out of the outside of you r Plushie.
This is a similar question to: Environmental Tolerance which has an answer regarding the temperature tolerance.