Yes, every wallet is going into the fork. And the empty wallets will be empty. And the wallets with bitcoins in them will have both BCH and BTC.
Yes, this is good strategy. To be clear, this only works if you move your bitcoins after the fork starts, not before.
oh now i understand, so only the wallet that are full after the full can claim even if they are empty afterward, it make sense now, so i don't have to move on exchange to claim right? i can calim at any time as long as my wallet hold btc after the fork? even within one year?
Yes. Even after a year.
You're not really claiming BCH. Instead, it's more like you already have BCH. Until the fork actually happens, "Bitcoin Cash" and "Bitcoin" are essentially just different names for the same thing.
Another way to understand this: Today, every bitcoin is actually 1 BTC and 1 BCH stuck together. When you send a bitcoin you're actually sending 1 BTC and 1 BCH at the same time. If you have 18 BTC in your wallet right now then you also have 18 BCH in the same wallet right now, it's just that your wallet doesn't display them. At the fork, we will all be able to separate our BTC and BCH, but the tools are all fairly new and little tested.