My and my mum are staying at disneyland Paris at the disneyland hotel form October 13-17th 2014 were both adults and we tried to book the castle club but it was much much much more expensive to stay at the castle club and to stay in the normal part of disneyland hotel. Can guests who aren't staying in the castle club have breakfast in the castle club restaurant or is only guests who are staying In the castle club that can have breakfast at castle club restaurant.
No, the lounge is only for people staying in the Castle Club
As never2old says this Lounge is reserverd for guest of the Castle Club.
But at your check in just asked what an upgrade to the Castle Club will cost. Often this upgrade-price is not that expensive or if the hotel isn't very busy they will offer it for free - just give it a try!