Love Clover! And River!
I like Jack as well. In the 40's and 50's people would use the name Jack as a nn for a lot men/boys. The author C.S. Lewis would go by Jack and President John F. Kennedy went by Jack as well.
Also, what about Jack as a MN?
Some FN suggestions:
Atticus, Bentley, Arlo, Jules (Yes for a boy), Cesar, Irving, Cedar, Garrett