Explanation:

Box 1: No
User1 is member of Group1 and has Device1.
Device1 is not Azure AD joined.
Note: Requiring a hybrid Azure AD joined device is dependent on your devices already being hybrid Azure AD joined.
Box 2: Yes
User2 is member of Group1 and has devices Device2 and Device3.
Device2 is Azure AD joined.
Device2 is excluded from CAPolicy1 (which would block access to Site1).
Box 3: Yes
User2 is member of Group1 and has devices Device2 and Device3.
Device3 is Android and is Azure AD registered.
Device3 is excluded from CAPolicy1 (which would block access to Site1).
Note: On Windows 7, iOS, Android, macOS, and some third-party web browsers, Azure AD identifies the device using a client certificate that is provisioned when the device is registered with Azure AD. When a user first signs in through the browser the user is prompted to select the certificate. The end user must select this certificate before they can continue to use the browser.
Reference:
https://learn.microsoft.com/en-us/azure/active-directory/devices/howto-hybrid-azure-ad-join
https://learn.microsoft.com/en-us/azure/active-directory/conditional-access/howto-conditional-access-policy- compliant-device

References:
https://docs.microsoft.com/en-us/azure/active-directory/conditional-access/concept-conditional-access- conditions#sign-in-risk states clearly that Sign-in risk

Explanation:

Box 1: Enable users to protect
Anti-phishing policies in Defender for Office 365 also have impersonation settings where you can specify individual sender email addresses or sender domains that will receive impersonation protection.
User impersonation protection
User impersonation protection prevents specific internal or external email addresses from being impersonated as message senders. For example, you receive an email message from the Vice President of your company asking you to send her some internal company information. Would you do it? Many people would send the reply without thinking.
You can use protected users to add internal and external sender email addresses to protect from impersonation. This list of senders that are protected from user impersonation is different from the list of recipients that the policy applies to (all recipients for the default policy; specific recipients as configured in the Users, groups, and domains setting in the Common policy settings section).
When you add internal or external email addresses to the Users to protect list, messages from those senders are subject to impersonation protection checks. The message is checked for impersonation if the message is sent to a recipient that the policy applies to (all recipients for the default policy; Users, groups, and domains recipients in custom policies). If impersonation is detected in the sender's email address, the action for impersonated users is applied to the message.
Box 2: Add trusted senders and domains
Trusted senders and domains
Trusted senders and domain are exceptions to the impersonation protection settings. Messages from the specified senders and sender domains are never classified as impersonation-based attacks by the policy. In other words, the action for protected senders, protected domains, or mailbox intelligence protection aren't applied to these trusted senders or sender domains. The maximum limit for these lists is 1024 entries.
eference:
https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/anti-phishing-policies-about