As their tea and coffee has been replaced with herbal tea, will any of the HMs get caffeine with drawal symptoms (headaches, nausea, irritability, etc.) Over the next 2-3 days? If so, what will be the result?

Maybe, i think it depends on the individual. I personally only have decaf now, as its too hard to come off the caffeine as i get really bad headaches. I dont think its good to stop caffeine all at once.. but to come off it slowly.

I've been on decaf for about 2 years now, for exactly the same reason. The headaches I got and general horrible feelings simply weren't worth it to go back to caffeine.