i agree, i think the A time before bed is likely a huge contributor to the NW. sounds like naps are good, and you are right to hang in there - the nights WILL get better. you are doing the righ thing watching morning A time and getting them down at the right nap time. don't be afraid to put htem to bed for the night at 5:30 if need be to keep that afternoon A time short. what will happen is that wake up will get later and then nap and bedtime will get to a better time. this isnt' for long, but it is what will help ward off the OT all together.
sorry to hear DS2 is fighting the teeth. good news about teeth is that eventually they come through and it is over. i remember thinking it was cruel that one would just finish cutting a tooth and then the next one would start. but it does pass. huge hugs to you - you are doing a GREAT job and this will fall into place. hang in there.