My dr usually says to go ahead and give a couple of doses of tylenol after shots because this is very common. It will help with soreness at the injection site as well. However, you need to get dosing from the dr. or look it up online. The bottle won't tell you the dose for a 4 month old. Go by weight, not age.
My daughter has No side effects from the CDC schedule, my son did, he would get fevers. Maggie brings up some urban legands and the info is not accurate. Japan actually sepereates the MMR shot and the rate of autism continues to increase there as well. The Dr. Sears book is great and it is the schedule I would go with if my daugter had bad reactions. She has never even been fussy, so I got lucky. If the shots did not give "true immunity" we would still have polio. I will keep the MMR combined, but won't do it until 2 years. I would definately recommend you not do MMR with the chicken Pox, that was the roughest for my son and the one series I regret doing. They are both live virus and too much to handle in my opinion. Definately feel free to play with the schedule, but I'm not convinced about giving one at a time. You go back more often and your child's immune system isn't given time to reset and be without the pressence of a vaccine. The immune system is always dealing with something during this type of schedule and I will be curious to see what research says about this a few years from now. You are the mom, go with your gut! I know, you asked about the fever, not everyone's take on vaccines! Tylenol in the right dose will never hurt!