Small addition Can more than one valid address be generated from a private key?
yes there are many different valid addresses that can be generated from a single public key (that is derived from a private key) like P2PKH, P2WPKH, P2SH-P2WPKH, P2SH (multisig), P2WSH (multisig),... each script hash can also contain different scripts with that same public key like P2PKH inside a P2SH.
read my comment again specifically the last paragraph.
Is knowing some private keys in HD wallets dangerous? Or sell wallet.dat files?
obviously yes!