My suggestion is to read the thread on washing yeast. It is a sticky in the fermenation and yeast heading. That will give you all the information you need. I have washed many yeasts over the years. They seem to keep for a pretty long time. Freezing them is not a good idea, unless you do it the proper way.
On Deck - Crabapple Wine
Secondary - Pomegranate Wine, Red Table Wine, Wild Fox Grape Wine, Blueberry Wine, Surly Furious clone
Bulk Aging - Brewtopia Barleywine, Sugar Beet Wine