It should be pretty obvious that you will have access to your seed, which you can use to import your wallet into a different wallet (like Electrum).
I'm not so sure... With the current ledger setup, after the initial setup and confirmation, there isn't (as far as I know) a way to get the seed mnemonic to display on the device again.
I believe this is a "security feature" to prevent the seed from being extracted or stolen etc.
I doubt the new native desktop software will change this behaviour.
Regardless, the user should have written the seed down during setup (and possibly made a 2nd copy as backup), so they *should* have access to the seed mnemonic and, by extension, the private keys.