Welcome to CLNC
There is a local community college in Jacksonville called Coastal Carolina Community College. It offers the usual courses that most community colleges offer around the country.
A little over a hour north there is ECU, East Carolina University, a very good school that's been around a long time.
To the south is UNC-W, University North Carolina-Wilmington, a state school. Both are good schools worthy of you checking them out. Once you are married to your Marine you will qualify for in-state tuition. You'll have to Google the schools I've mentioned and compare the costs for yourself. I've gone to ECU and found their rates are very reasonable.
As far as the base goes, there are day care centers, but they are usually booked solid, so I'd suggest once here checking out some of the civilian centers. Also, there are always people that run small day cares from their homes.
Camp Lejeune is right on the Atlantic Ocean, lots of water activities to do. Base housing is available, but like most bases there is a waiting list, so you two will most likely have to rent a place in town.
I've lived in the area for over 20 years and would be happy to answer any questions you may have yet.