You may be able to use a 6.5 gallon carboy- I never have, but you don't get much krausen with wine. The thing is, many kits have "things" to add during primary- say, grape skin packs in a hops bag, or oak chips, and buckets make it much easier to deal with.
You need a 6 gallon carboy for secondary. I use star-san all the time, for all of my gear, and it works great. You may want to buy some k-meta (or campden tablets), since the kit will recommend you add some at bottling if you want to age the wine but it doesn't come in the kit.
I got most of my wine bottles from dumpster diving, er, visiting a recycling center.
You need 30, but it shouldn't be hard to get 30 before bottling day.
I never rehydrate my wine yeast, or make a starter. Grape juice is the perfect food for wine yeast, and you don't even need yeast nutrients for wine kits.
A large spoon, plastic or stainless, is needed for a wine kit. All the kits I've seen have you add a gallon of hot water to the primary, and stir in bentonite well, and then add the grape concentrate, juice, skins, etc, and then top up with cool water. I do that right in my kitchen sink.
One silly tip (put this in the "I wish someone would have mentioned that to ME" category):
- those lids on the grape concentrate are almost impossible to remove without either a. breaking the cap, b, splashing the concentrate everywhere (and it stains) or c. both.
I keep the bag in the box (so you don't accidentally squeeze it, trust me on this!!!!!), and then use one hand to hold the cap and a big wrench in the other to pull it off. If the bag stays in the box for support (it's very squishy), you're less likely to spill a quarter of it before you try to pour it in the fermeter.