I want to reassure people about their wallets during this chain fork.

The wallet.dat files' primary purpose is to store the private keys to the addresses you own.

It does contain a mini ledger of sorts so that the client/daemon does not have to re-scan the entire blockchain every time you start it.

The transaction/balance information in the wallet.dat file is not "canon" so to speak. It is really just there for display purposes.

The true balance/transaction information is in the block chain itself. When the Client/daemon detects that the blockchain might not match the ledger in the wallet file, it will re-scan the blockchain and correct the balance/transaction information in the wallet.dat. This normally happens when a chain reorganization takes place, or a new/different wallet.dat file is presented.

When the resolution of a fork occurs, all transactions on the rejected fork no longer exist. If person A sent 10 coins to person B and they were on the rejected fork, person A would have the 10 coins back in his wallet and person B would have never received those coins because the transaction no longer exists.

The people that have the potential to lose coins are those who mined POW blocks on the rejected chain. Those will be lost.
Although the coins gained on the rejected chain through POS would disappear, the coins that were used to stake a block would still have the same maturity as if the fork did not happen and will stake new blocks on the correct chain.

Take all the precautions you wish, whatever makes you comfortable. When the correct chain is decided, your client/daemon will automatically adjust your wallets ledger.


ETA: This only applies to transactions after the fork. Any transactions before the fork are unaffected.