Nice covers by the excellent Nick Cardy. These came out around 1956, a little before I started buying DC comics in earnest (too young, no money). Trying to spot the artist (I'm not real good at that), my biggest clue was Dan'l's face in #1 - it reminded me a lot of Aquaman's face in his run in 1962, drawn by Cardy.
Thanks! I was wonderin' who did these.