Yes, they can be made from anything.
There are duvets of such stature. You can search for them online or call your local furniture store to see if they carry them.
There are some hypoalergenic ties, but they are rare and fairly pricey.
Duvet covers come with many different types of closures depending on the manufacturer. Most duvets close with buttons, ties, zippers, or snaps.
there is no such thing as a hypoallergenic cat
Draper and Bedding is reputable and provides custom duvets.
Nautica Fiji Duvets are a great buy,and a value for the money.
Sometimes they might slip out of the comforter, but they usually don't. If you get a comforter with Egyptian cotton or a high thread count, you should be okay!
A hypoalergenic dog. (doesn't shed)
Yes, you can put a regular comforter in a duvets cover. Before purchasing either a comforter or a duvets cover, measure the item that you have and make sure that the comforter will fit the cover and vice versa.
Yes, the "rest Luxury Jacquard Duvets" are machine washable and should be tumble dried.
gGenerally, JCPenney provides good quality duvets for reasonable prices.
Hotels typically use duvets on their beds, as they are easier to clean and maintain compared to comforters.