Maybe not with really small children unless you are watching them very well. They can easily get burnt around the fire or lost in the dark if you are not too careful.
No reason not to go unless you are about to have your baby any minute.
Do they work? If not, let them take her for a couple days during the week while you're at work. They'll get to spend tome with their beloved grandchild, and you'll save money on childcare.
Since they both work full-time, maybe you could pick one night every week to bring her over there for a...
Children come in all shapes and sizes, and being tiny *may* be the right size for your niece. However, *if* her diet is as limited as you say it is, there very well may be a problem.
Unfortunately, there is very little that you can do without the support of her mother. If she was in your care...
Yes, as long as it is well ventilated and the baby isn't in the actual room. Also you can get paint with low VOC. It hardly has any odor at all and is very environmentally friendly. Its usually a little more expensive, but very worth it. That's the only paint we use.