4.
I understand it so:
<wif_key> == wallet_dump_account_private_key <account> "owner_key"
in case of damage I can run the command:
wallet_import_private_key <wif_key> [account_name] [create_new_account] [rescan]
it means:
wallet_import_private_key <( wallet_dump_account_private_key <account> "owner_key")> <[previous_account_name]> [new_account_uniqe_name] [rescan]
Yes .. and if you registered you account on the blockchain you can import your account simply by
wallet_import_private_key <wif_key>and the wallet will figure out the rest ..
once you reimported your account .. you can regenerate all keys every been generated by issuing wallet_regenerate_keys as described in the wiki
3.
I understand that it is safe to import one of the three accounts on another operating system with a command from point. 4
Jup .. only exception would be if you imported private keys into your account from elsewhere (e.g. imported AGS funds, or sharedrops, or what ever)
all keys that have been generated deterministically by the client or TITAN can be recovered by wallet_regenerate_keys