Chromebooks are not really prone to getting viruses. The most important thing is not enter personal/secure information on websites you do not trust. Norton LifeLock could be used for identity theft protection and damage reimbursement, but it's not really going to protect you from much on your chromebook. A more useful tool would be an ad blocker like "uBlock Origin" which you can add by going to the google chrome web store and searching for "uBlock Origin" and clicking "Add to Chrome" and then clicking "Okay".
Your chromebook should have built-in speakers to establish sound. If you would like earphones so that no one else can hear your Zoom conversation, then you can use those instead.