Most mining rental websites will charge you a price above what you can expect to earn by using the hashpower
Yes, at least it currently seems so.. The person who borrows money does not only have to take the loss by renting hashpower but also has to pay the interest rate..
Maybe times will change concerning cloud hashing services..
hashpower rental sites will have no reason to charge less then wheat it would be expected they would earn by mining themselves.
It really only makes sense to rent hashpower if you are trying to test something/do some kind of research or if you are trying to attack a pool/altcoin
Yes. People who rent it usually rent them to hash new coin.