It's very possible I misunderstood some of the rules, but if not then this is my solution:

Alpha works every morning on Ground, except for two weekends (= 4 days off). Bravo does the same days on Ground but in the evening. Charlie works First on weekdays (= mornings only) and Ground mornings on one of Alpha's free weekends, the remaining weekends are time off (= 6 days). Delta does the same but with Second and Alpha's other free weekend. Now we only have two weekend evening shifts on Ground left (when Beta has days off), which are done by Echo (who gets 26 days off per month). Of course this could be distributed more fairly, but that was not a requirement.