Welcome to the wonderful world of of being a cat slave! :D
1 - World's Best Cat Litter - I seriously recommend this, though bit more pricey. It's made of corn and still clumps. Problem with other clumping litters, is that there's a chemical that's toxic for cats when they lick their paws afterwards to clean. It clumps in their stomachs and can sometimes kill them! My cat has NEVER refused to use this litter either, except once when she couldn't get to in time cause she was sick.
2 - I recommend ones that aren't made w/ animal-by-products and don't have rice as first ingredient in their descriptions. However, some cats are so picky you have to go with that can eat. Mine goes for Purina (wet and dry). It's good to do both, for wet helps them from getting dehydrated. Also, buy it at PetSmart! If your cat doesn't like it/won't eat it, you can bring it back for a refund! Even if opened (tho of course not half-all gone). GREAT place until you know what your cat will eat.
3 - Scratching posts - I recommend the stand-up pole ones that have the twine-like ropes on 'em. DON'T use the carpet ones, because the texture/feel of 'em make them think it's ok to do the SAME THING on YOUR carpet :) You may need to gently imitate the motion in front of your cat on the post at first so they get the idea.
4 - Best toys, it really depends on the cat! Mine loves the cheap little mice and brown paper bags. Have to experiment and see what your cat will go for! Start cheaper, you'd be surprised what they like :D
5 - Mine is indoors only and I recommend collar and tag of course. Debate is still out on microchips because the scanners aren't universal :( Shot in the dark, but not guaranteed, your choice. Also, maybe try getting scented stuff that is made to specifically repel cats and put it near the door if you're that worried. However, make sure non-toxic or NOT allergy-inducing. You won't have them greeting you at the door though.
** In addition, I recommend pet insurance NOW while they're still completely healthy (so won't be rejected for 'pre-existing conditions') and keeping up to date with ALL shots. Figure out your vets (check reviews) for regular and emergency BEFORE it's needed.