Securing a wallet and multiple addresses I am trying to understand Bitcoin QT. Sorry for the questions.


If I create two new addresses, then encrypt my wallet and then create a third new address after the encryption process, are all three new addresses encrypted and safe to use?
If I then copy the wallet.dat file to usb sticks and delete the wallet.dat file on my laptop, are the funds on the usb stick still accessible? On all three addresses?
Can I then continue sending money to these addresses? Even thought the wallet isn't connected to the internet?
Imagine I have a copy of the wallet.dat file on a usb stick. If I generate a 4th address on my laptop, and then destroy the laptops wallet.dat file, will funds I send to the 4th address still go into the wallet.dat copy  on the usb stick which was made before I created the 4th address?
If I can see coins transfered to my wallet and confirmed, should I bother setting up a second wallet on my other computer and doing a test transaction with my new funds? Or can I safely assume the coins are ok?
Is there a gauranteed fail safe way to check the balance in an address without hooking up the wallet.dat file to my client? I want to keep my wallet.dat file offline.
Are the answers to the above the same for Litecoin QT?


Thanks so much for any guidance
Yes, your "wallet.dat" contains all your keys, and when you make new keys then they will be added to your wallet.dat. If you encrypt your wallet.dat, then all keys in it will be encryptet and all keys added to it will also be encryptet.
Your founds is not stored in your wallet.dat. The founds are stored in the blockchain (which everyone can download via a huge p2p network).
Yes. Your wallet.dat only contain the private keys to spend coins. Everyone can at all time send you coins (whether your connected to the internet or not).
No. The USB stick will only be able to spend coins send to the first 3 addresses (as the USB stick's wallet.dat will only contain private keys to the first 3 addresses).
As long as your client has the longest blockchain, then coins send to you can NEVER be removed again (unless someone spends them, with the private key only you know). However note that coins can first be "trusted", when there is enough confirms ("0 confirms" just means that someone has sent you a transaction, but it will first be "trustable" when it's included in the blockchain and enough blocks confirms that the blockchain will never be forked under your transaction. But usually 6 confirms should be enough).
Type your address on a trusted website, e.g. https://blockchain.info/ and look at the balance. Some clients support "watch-only" addresses (they only store your bitcoin address and not your private key), but I don't think Bitcoin-QT supports this (yet).
I don't know much about litecoin, but most of the "public/private key" stuff, apply to all cryptocoins (e.g. you can watch an address without storing the private key, etc).