I've never crossed the two but have crossed both with other breeds.
Feather footed is dominate and will be passed to the offspring. Of course that's if the cochin is pure for it and not only carrying one gene herself.
The offspring will only carry one gene and most if not all will have less feathering then their mother.
The long tails is a different story. I was told that there are more then one gene involved in long tails. The length of the tail was dominate the others recessive and the non moulting wasn't even present in phoenix.
When I had crosses they didn't seem to get long tails maybe just slightly longer then the other breeds tail and never got the long saddle feathers.
With the cochin tail type I myself wouldn't expect any type of long tail.