I have those pants and wanted you to know they shrink a lot. The 3-6 month ones shrunk down to more of a 0-3 month size after washing and drying.
I just bought this in size three months: http://www.zulily.com/index.php/boys-bubble.html
And this in size preemie: http://www.zulily.com/index.php/blue-257286.html
Hoping that one of them will fit for the newborn pics I'd like to have taken and/or as a birthday outfit. I also think either would be appropriate for church and the wedding we are supposed to attend when he is a few weeks old.
That is a really cute outfit. I love Winnie the Pooh. I just went through my bins and had to specifically make sure to choose "newborn" sized clothes for the coming home outfit. I remember with DD1 that I had a 0-3 mth outfit thinking that was fine. She was swimming in it and it was hilarious. I love how they are still like a little frog with their legs all crinked up the first few weeks.