I never worried about noise, they will sleep through it if they are exposed to it. Its the babies whos parents are so careful to be quiet that will wake to any noise I can vacuum the whole house and all 3 kids will sleep through it lol
This is what I was told when I was pregnant too - so I was determined to make noise while DS was sleeping so that he would be a "good sleeper". However, DS has ALWAYS been a wakeful baby - and particularly sensitive to noise. I gave up putting his bassinette in the loungeroom, or letting him sleep in the pram etc. because he just wouldn't settle with household noise.(Just showing you the other side of the coin - leaving the door open & making noise etc. doesn't necessarily mean that the baby will learn to sleep through it).

Anyway, re. co-sleeping - because my DS is such a light sleeper, I sleep in DS 's room on a king single & DH sleeps in our room. DH gets up early for work - so this gives us a better chance of keeping DS asleep. (now, before you think, "how horrible to always sleep away from DH" - I do actually start the night in my room & DS in his cot, but I co-sleep with DS once he wakes up about midnight).

You certainly can co-sleep on your bed during the day if bubs is not rolling around (nothing nicer than a sleepy cuddle in the afternoon ) - but once bubs is rolling around, you may want to use a mattress on the floor, or put bubs in a pram/sling/cot). DS does his day sleeps in the cot - but I still lie next to him & hold his hand until he falls asleep.