Thank you for the in depth reply! This helps :) I also appreciate the challenge of communicating some of this stuff to us dang non-super-technical folk!
Another good piece of advice I heard is to create a brand new Hive wallet exclusively for cold storage—this would remove some of the puzzlement around changing some/all of your keys. The cold account could easily (I assume) delegate stored HP to your "main" if you wanted to retain curation rewards and the like. There'd be some futzing with transferring the HP from a substantial main of course, so always pros and cons!
RE: Hive x Ledger: Support for Ledger Hardware Wallets