Does the zcash wallet’s key pool have z_addresses? I’m wondering because I made a backup of my wallet.dat and then used the z_getnewaddress to get a new z_address, and wanted to know if I need to make a new backup of the wallet.dat, or if the new z_addr came from a key pool that’s already in the wallet.dat file I backed up.
I’m using the standard command line wallet on Linux.
Yes, you should backup any new address you generate. You can either backup the whole wallet again or dump the private key for newly generated addresses. You can read more details about backup options here: https://github.com/zcash/zcash/blob/master/doc/wallet-backup.md
What about for new t-addresses, new backup required?
Yes of course. You should regularly back up all your stuff anyhow.