I have to agree that twins with a toddler is much more challenging that I ever imagined. The babies are easy compared to the toddler since meeting their physical needs typically meets all their needs. The toddler is another story.
So...if there's anyway you can learn to tandem, do it. Do you have a nursing pillow? When they were newborns I could lay both of them on there and then spend the entire nursing session going back and forth between latching one and then teh other. It was exhausting since neither was a good nurser, but it worked.
We did lots of tv and movies.
We also did lots of stories. Almost every time I was stuck nursing I tried to read her a story and we still do them when nursing the babies. We also did puzzles, crafts, basically anything I could do with her while sitting still (usually with a babe at the breast).
Friends, neighbors, church members were all a blessing. Dinners were awesome and always accepted (asked for) when anyone asked if we could use help. Freezer casseroles were awesome and used for months.
We too used formula, so no flames here. However, when I was able to wean off of formula (supply issues) the nights became easier. I was able to learn to doze off sitting up in bed with both on the pillow latched on. That was something I couldn't do with a bottle. Now I just alternate side lying nursing with them. I'm still up at least 6 times a night, but more rested because I can just lie down with whichever baby needs me and then switch when the other cries.
As far as scheduling, I'm not much help as it's all a blur. I did try and do everything in tandem, if possible. This way I had some idea of who did what, however I was never able to keep track of who drank how much from the bottle since they shared bottles.
It does get easier. Now, at 8 months, they both think the toddler is the best amusement ever. THeir faces light up when she comes in the room and their eyes are constantly following everything she does. Now, I will admit that DD1's behavoir got worse before it got better. All due to my lack of time for her, but we did survive and hopefully it will just get better from here on.