I am a manufacturer of tea kettles and would be interested in learning what you would be interested in as far as seasonal tea kettles? Whats important? Design, function? What holidays? Xmas, Thanksgiving??
There are different circumstances that put different requirements on the kettle.
Function is always important, unless you want a statue. But then I prefer a real statue or candle holder.
Personaly I would go for something that I can use year-round, but then my season parties are never at my place.
A good/very nice design that does not reduce functionality is a pre.