1. Those using Trezor, what additional security they can do to make sure they are safe apart from trezor PIN
Protect your wallet (Trezor one or Trezor T) from physical theft. A physical attack on it can be used to reveal its seed phrase. Or best to use a passphrase to generate the keys and addresses along with the seed phrase.
2. It sounds weird but when one creates 12 keys in any btc wallet then either user knows his 12 words or this wallet knows these 12 words.
Is it it possible to hack this 12 word from btc wallet software.
If another person knows your seed phrase, the person can use online wallet to have access to your coins and spend it.