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If you're bringing a laptop, then you can probably keep it down to 2 cards (1 as a backup). I'd say you'd probably want at least 16gb cards depending on how much you shoot.
If you're not bringing a laptop, you'll want to bring enough cards to fit the pics you'll shoot. I know I have trouble shooting more than 250 shots a day, so I can plan around that. I don't know what that number is for you. Backing up your photos may be a challenge in that situation, but if you spread your days out over cards, then the odds of losing data go down.
Anyway, storage is cheap (relatively), so can't hurt to have too much.
I'd probably bring at least 3 batteries if it were me.
50mm is a little long on a crop body, you may want something a little wider. I don't have experience with those sigma's though.