4) my understanding is that if the BTC core wallet has "HD" in the bottom right, i don't need to dump the private keys, as the backup/wallet.dat file will have all that info. is this correct or do i need to make a physical backup of every private key as well.
Yes, the backup of the wallet files are enough but make sure that the backups are made
after you've encrypted the wallet files.
That's because it'll generate a new "
hdseed" after encrypting the wallet, making the old backups obsolete.
2) I have actually created a backup file already, but the backup file that is created does not seem be a .dat file. when i save it to a USB stick or DVR and look at the file on a windows computer the file type says "21 file". is that correct or is the back up more than just the .dat which would be contained in the overall backup file?
Windows has an option to hide/show the file extension but since it says "
Type: 21 file", it means that the extension isn't "
.dat" which shouldn't be the case with "
File->Backup Wallet".
You can display the extension in Windows in the 'file explorer' menu "
View->File Name Extensions".
however, i suppose that is how i need to do it to make absolutely sure i have the right file/files. If i have two wallets created/set up, will each wallet have its own wallet.dat file? if so, how do i tell them apart? sorry, i know these are likely very basic questions.
Yes, 1 wallet = 1 backup with "
.dat" extension.
You can set a name when you use "
File->Backup wallet" but make sure that the correct wallet is selected in the "
Wallet:" drop-down menu at the right,
you can also set a wallet name during wallet creation (
in the later versions). IMO, naming those differently is enough to tell them apart from each other.