Hi T.,
Okay, new to group, and this is my first response, and it goes against most of the advice so far, but it's based on first (and second-hand) experience. As for the pacifier issue, my daughter started using one at 2 months because we were concerned about her having inner ear discomfort during an upcoming 3000 mile plane trip, and we just stuck with the "plug" after that. Then we switched peds (out of a huge university practice into a more personal private practice, and our doctor was great but adamant about giving up all artificial nipples by age 1. Daughter refused the sippy cup til my husband and I both sat down at dinner and drank from sippy cups, then she decided it was ok, and has been fine ever since. As for the pacifier, it was not so simple. I tried cold turkey, and as she only depended on it at sleep time, we spent a day of miserable crying with no sleeping, so I relented and gave it back. Then I took 2 of her spares, heated up a needle, and poked a hole directly in the end of the nipple of both. Washed well, and took a few experimental sucks of my own - blech! the inside tasted yucky and rubbery/plastic-y, so effective taste aversion as well as complete change of mouth feel. Every nap and sleep time after that, I gave her the modified pacifiers, all sweet and innocent-like, and she'd get pissed and throw it out of the crib. I kept returning them, playing dumb, and she kept tossing them, and decided for herself that it wasn't worth it, and never looked back. Just my own solution, not necessarily a cure-all, but after watching my baby sister use a pacifier until age 4, I was not keen on repeating that (I was a thumb sucker until age 8, for sleeping). She's now a secure and well adjusted 4 year old, and only marginally insists on her life-long tigger doll as a sleepy comfort object. My thumb sucking resulted in 5 years of braces and headgear (torture devices that just beg to be taunted) to undo the bugs-bunny overbite.
Good luck, and I offer only the advice I would give my first-time-pregnant baby sister (age 25, not a baby anymore, gosh am I old).
As for the co-sleeping issue, I can only offer a caution based on my good friend who still battles hours into the night to get her 3 year old to sleep in his bed, but once she drops from exhaustion, he's like velcro back in her bed (single mom). Nip it in the bud? Your twins seem to like using each other as co-sleeper, and they'll eventually want their own space as they mature. Be strong and confident! You will eventually want your own space and tire of 3 year olds pulling your eyelids open and poking at your face to pass the time (this from the victim mom's mouth).
Anyway, wing it, you'll do fine either way, babies adjust to anything.
Rock on T., you seem like a perceptive and caring mom, and that's really all your boys need.