what is the length of time in the spring between the time bass hatch and bg hatch?

bass usually a few weeks earlier?

In our pond cnbg have already had 2 spawns and both were before my lmb spawn.

LMB just before the BG so they will be ready to feed on yoy BG.

The best answer is "it depends". Spawning is a combination of photoperiod and temperature for largemouth bass. It's more about temperature for bluegills. In Texas, you'll often have bluegill spawns during bluebird, warm January days, then again in early March, before bass are even on a nest. But, they may even be spawning at the same time, with bass on solitary nests in 4-6 feet of water, with bluegill in nesting colonies in 6"-12" of water.

Don't both BG and LMB time their spawn around a full moon?

There is evidence that they spawn around the full moon. It is not a 100% certainity though. The best way to state it IMO is the major spawns occur around the full moon. There are other factors at work like temp , photoperiod and weather in addition to local factors.

So, perhaps I'm not totally correct when I see the full moon in the summer and I tell Jodi... "Full Moon... The fish are having sex!"

Bass spawn in phases of the full moon. So do channel catfish.

My cc are full of eggs you think they will spawn this next full moon?