With the alarm I think you will be fine. We moved ds to his own room at two weeks because I am a very light sleeper and even when he was asleep and quiet in our room, I was not getting any sleep. It was awful! Out he went - it was the best for all involved.
DD2 is 6 months old and a very noisy sleeper. At the moment she is sharing our bedroom but wakes two to three times a night and sings and shouts, for an hour or so at a time- not in a distressed way, I think she just wants to be up and playing, she's a very spirited baby! She has also been teething recently which is probably contributing to her wakefulness. Because we are so desperate to get some sleep we end up giving her the dummy or cuddling her back to sleep- but I know she would settle herself eventually if we left her alone, as she does during her daytime naps. We would move her into her own room (as we did with DD1 at 6 months), but we're in a two bedroom house and DD1 has the second bedroom, so I don't want to move DD2 in there until she's regularly sleeping through, so as not to disturb DD1's sleep. We do have a small walk through room which is big enough to fit a cot in, but it also has the airing cupboard (with combi-boiler), and no window. My instinct tells me this wouldn't be a safe place for DD2 to sleep, but wondered if anyone knew any different?