Luke went through a horrible stage of being up 3 or 4 times a night and it was a killer Dixiebell, although not always for milk, so I totally feel your pain!! I can see where you're coming from with having a third but I can't honestly say I would definitely feel done at 3. Perhaps when I got there as I know a few people who say having a third is much more than adding one more, more like doubling the work!
Yay for a pink one SilverBirdie! I think it's lovely to have one of each, you get to experience both. Having said that mine are the same sex and couldn't be more different!!! I have a friend who has a girl 4 months only than ds1 and a boy 6 weeks younger than Luke and she's very negative about boys :( Her girl was so easy and lovely and her boy is quite boistrous. Well my first boy was like her girl and second boy is like her boy, so I think a lot has to do with being second born (from others I know too) but I love him and all the hard work he brings and he has so many lovely/positives that ds1 doesn't have that's makes the 25 min tantrums and kicks/punches/bites worthwhile. I have a friend who has 2 dd's and she won't have a third as she says she can't be lucky enough to have a third girl and really doesn't want a boy :( I used to work with a man who wanted 4 girls, he was one of 2 boys who didn't get on and he had this idea that you needed more than 2 so that they'd find a sibling they liked and that girls together were much better! My two are boys and best buddies but me and my brother did so much together and so did dh and his sister. I think what I'm trying to say is that whatever you have you will love and that a family is what you make it not what sex/order/number of children you have.
On the bed front I would go for straight into beds and the rooms they are going to go in sassy34264. Then this room will be where you have a bed and will be on your own and you won't have a struggle to make another change. I'm probably not describing that very well! My friend did this with her dd, when her and her ex broke up and she moved she used that as an opportunity to put her dd in a bed. The bed was in the new house and the cot was at the old house.
I will warn you I've had several friends who have moved to bigger houses so their children have separate rooms and have ended up with them in the same room as they've got used to sleeping together and didn't like being alone! One friend now has the problem that her dd (6) wants her brother out but he loves his big sis, so all his stuff is in his room so she has her own space but he still has his bed in her room and sleeps there as she kept finding him in bed with her anyway 