Nice little thing to do! Since c5 are always obsessed wth xmas and inapropriaty always do it in the summer, what I think is that BB should have an actual proper xmas special where as many housemates as possible from the 3 series of that year reunite have christmas dinner and stay the night!
maybe like film it in November and air it in December and maybe on 5* to not make BB so tiresome and air it just for fans, I think a lot will be against this but I like the souns!