The only thing i can tell you is that it does get better with time. I HAD to give my twins rice cereal in their bottles for their gerd and trust me it didnt help them sleep any better, they still woke up every 2 hours! At least you are getting a 4-5 hour stretch! You are lucky there. Around 4 or so months things start to get easier, at that point the bottles get fewer and fewer till you can stop them completely but for now all you can do is grin and bear it.
Nothing you can really do about them waking each other up, my twins are 9 months old and if one is screaming in the night the other still wakes up. They will never grow completely immune to it, but they do learn to ignore it some. Try putting them in seperate cribs if you havent already.
But yeah thats twins! They are really hard in the beginning, but they do get easier!