Please secure both WalletB.dat and WalletS.dat. You need to backup them (ideally after you have encrypted your wallets) and later replace them back after the wallet has synced entirely. The other wallets are for other currencies you can’t obtain yet, so you can leave those as they contain no funds anyway.
The syncing should not be hindered by your wallet files, it is mainly a precaution while you are about to delete the blockchain files. It is easy to delete all and there is no way to retrieve your funds when your wallet files are gone.
Please let us know whether the syncing actually happens or not after you have replaced the downloaded blockchain files and you started the wallet. After that it can still take several hours until it has fully synced. If it doesn’t sync, please ensure your internet connection is working. The next step would be adding nodes in the config file.