The advice is to use the same cat litter as the breeders do, for the first weeks, than you can change to other cat litter, without problems. They are also very curious. An open drawer is an invitation. As are doors, windows and cupboards. Even after 13 years with cats, sometimes they still amaze me.
Fleas can be a problem during the summer and warm periods.
Only use products which are specifically made for cats. As there are many different products, you can always ask advice from your vet. Last update was March, 2nd, 1997.