If you can afford it, it’s wise to dedicate a separate machine for handling your wallet synchronizations that doesn’t do anything unsafe like downloading questionable torrents and surfing new websites.
It's pretty unnecessary. Hardware wallets can actually be used with infected computers and hence why they're a preferred method of storage. Its unrealistic for someone to get another computer just for Bitcoin.
A good anti virus and some prudent measures are generally enough.
• Hardware wallets are a good option if you’re willing to spend some money and like to access your wallets somewhat frequently but worry about residential theft. A hardware wallet, if fallen into the wrong hands, prevents thieves from accessing your coins as would a safe. It does not keep a backup of your private keys, however, so again make sure you can access those even if your hardware wallet is stolen.
It isn't what it's designed for. While hardware wallets are reasonably hardened against physical attacks, they're primarily used to guard against malware and use on compromised computer. They can defend against physical attacks but it'll be way better to keep them in a safe instead.
• If you do choose to buy a hardware wallet only buy from reputable sources – preferably the vendor itself. Amazon used to be a safe place to buy from but they have been mixing their inventory recently and many people are receiving Nano and Trezor wallets that have been used or at least the box was open. Understand how seeds and wallets work before dumping all your coins into one.
It's okay to buy from the third party if you've the technical knowhows to wipe the device completely. Border agents tends to open the package and inspect the device and it's safe as long as the seal is not broken and that your device is not opened physically.
• If you have any intention of sharing your coins with others in the event of injury or demise, make sure those involved know how to access the public and private keys. Making a convoluted 97 letter password is not a good idea if you’re the only one who will ever know the password.
Multisig could be a possible way to store Bitcoins. Try exploring that.
Other than that it's comprehensive. Great work.