I took DS out at about 18 mths and he wasn't bothered, but has woken himself up cold every night since then..... He is 4.5 now.... And just the wiggliest sleeper ever.
DD LOVED her sleep sack, so I left her in one until over 2.5.
Your LO probably has a comfort attachment to it, and I would therefore leave them in it until she is bigger. There is just no point taking it away really
. My DD has a rabbit that is her lovey, but she is also very attached to having a fleece blanket in as well. I started using it when it was cold and she had just stopped using the sleep sack (actually she got a bit too big for it and started to wake getting stuck and tangled up in it, so then she transitioned out very easily), but now she is attached to that as well.
LOs need there comfort items for good sleep, and sometimes that ends up being the whole bed and bedding etc. I think that is what your LO has done
.
Kids are so funny about their beds! My DS currently sleeps with a duvet, a fleece blanket, his mama bear, 2 old muslin cloths, 3 more bears, a very large crocodile and a snake
.