Hello Ken -
You got it! Don't delete the Yubico OTP credential in slot 1 (unless you never plan on using it). However, even deleting the Yubico OTP credential, you can program a new one that will work anywhere that accepts Yubico OTP, with the exception of Salesforce (
https://www.yubico.com/products/service ... ey-upload/).
Aside from the credential in slot 1, there is really nothing you can do to harm the key. If you use ykpersonalize and disable OTP mode, all apps except the YubiKey NEO Manager will not be able to recognize the YubiKey until you re-enable OTP mode. Otherwise, play around!