M.R.
I have a 2 year old boy and a 3 month old girl that we just moved into the same room. It's been working out well. We moved story time into our bedroom with my husband while I go through the baby's bedtime routine and put her down. My son still sings himself to sleep, but it doesn't seem to bother the baby. If anything, I think it is soothing to her to have him close by. The baby is still waking up 2-3 times a night to nurse, but my son rarely wakes up or stirs. Sometimes I nurse in their room, but most nights I go across the hall to our room. The chair is just more comfortable in there. I don't think it would really matter though. We also have a monitor in their room, but don't really use it at night. More so for nap time. Good luck!