Easter and Southern Red Cedar are some very stable woods.
It's strange that you experienced splitting unless you left them in the sun. That might have done it.
It is common for the wood to be bright red and then oxidize to a brown in just a few minutes. It can be brightened back up with sanding. Sealing the wood with a sanding sealer or varnish will help it to retain the color.
Cedar is best sawed fresh off of the stump. With time, the white sap wood, in a log, yellows. Fresh/green wood has the best contrast and it keeps it fairly well after sawed into lumber.
The lumber will split as you saw it. It is brittle and the internal tensions, as well as the stress from a dulling blade will allow it to split. Sometimes this comes from over clamping.
Generally, it is quite stable and won't split or warp. I dry mine under a pole barn where it is out of the sun.
