This should be possible.
This is expected.
You could check the db for recovery links using info in this recent post Can not send test email, create any user, or get authentication email back from passbolt at login [mail host blocking From: address] - #7 by clayton
What version of passbolt was used before? User keys are kept in the db so although the public and private server keys may change, and the users would need to acknowledge that upon recovering their account in the new install, the critical data should be there.