M.T.
I never had gastric bypass surgery, BUT I am a mother to 4 1/2 yr old triplets and also president of the Monroe County Mothers of Multiples. Which is a support group for mothers of twins, triplets and more. I have been part of this group since I was 4 months pregnant with the triplets and it was God sent. Getting involved with a group when you are pregnant is the best thing you can do. This way you can build some relationships before the babies come and people you dont know are offering help. What city/state is your daughter in? I can help you find her local group if she is in Michigan or if she is out out state (or in MI for that matter) you can go to www.nomotc.org (National Organization of Mothers of Twins Clubs) and down the right hand side is a place to put her zip code to find her local club. Good Luck and Congratulations.
Also, when you purchase bouncy seats and such I would suggest getting two different models. Double the toys, so when they get bored with one you just switch. :)