I don't get No. 2 either. How are you supposed to get 2FA codes from a password manager? Does it mean use a manager that has an OTP code generating feature?
Yes. Bitwarden, for example, lets you store the 2FA information for accounts. You would still use a separate 2FA app to be able to access Bitwarden, of course. It may slightly lower the safety of using 2FA, but assuming you're using a strong password for your password manager and require 2FA to log into it from new devices, it's a minimal risk, and probably no worse than the alternative of having them on your phone. Plus, if your phone is lost, you don't have to go through the hassle of regaining access to everything.
Yes, 1Password etc can scan the QR code and generate OTP codes.
For shared accounts this is often critical, where say, IT staff need to have 2FA access to manage some line of business cloud app, but you don’t want to setup 20 named users in your IT department in 30 different apps (Adobe, CRM, etc).
Password managers geared toward IT will have good audit trail, so each employee still 2FA’s into the password manager, and it’s logged who viewed passwords/codes when, so you still have named visibility into which IT staff are making which changes.
PassPortal (by N-able) is one I’ve used that did this for IT teams.