the others have pretty much answered your questions, but for what it's worth, here's what i do with dd (and did with ds): i co-slept, and put baby on bed during the day until old enough to roll off (i usually put a bolster each side of bubs in the day, just in case).

when ds was old enough to move round i put my bed (futon) straight on the floor and slept that way for 2 years. it was a pain making the bed, but it meant i eliminated all worries about falling out of bed in the morning. i haven't yet done this with dd, even though she's practically walking - i'm trying to teach her how to get herself off the bed safely, and i listen closely to the monitor so i can catch her the moment she wakes. that said, she did fall out of bed once during the night, but the bed's very low so it wasn't that big a deal.

as for noise, my kids are proof that the 'make a lot of noise and they'll sleep through anything' technique doesn't work for everyone. ds was the lightest of light sleepers - to the extent that there was one set of sheets i eventually stopped using because they were too stiff and crackly-sounding - but since the age of 3 or so, he's the heaviest sleeper in the world, which i like to attribute to his sense of nighttime security! we can turn lights on, move him around, open drawers, tidy etc and nothing will wake him. sadly, my baby is another light sleeper so we're once again tiptoeing around... the low, constant sounds are no problem but the high-pitched sound of her brother's voice is guaranteed to wake her!

good luck finding a good way to share your bedroom. hopefully your baby will remain a nice heavy sleeper and you'll be able to walk in and out of your room without fear!