Do the adobe reader speed launch and the synchronizer have to load at startup? Also what do these two things do?

I think the speed launch sound like it preloads a few things, so that when you want to read PDF docs, they come up more quick.

Not sure about the synchronizer. I normally turn this off.

If you turn them off at startup, you shoul dbe able to enable them again if you need them.
Well done for trying to clean up your startup though. :)

I certainly don't think they are critical at all.

Neither are needed at startup.
You can quite happily remove them as well as any scheduled updaters for things like Java, Real player, Quicktime etc.