If you are using Log Insight 4.0 then we now have a central user alert management. You need to have admin privileges to use it. You can then add multiple subscribers to the alert you created.
In general we cannot share alerts. You have to create a user 'shared' with a password you share with others and then create alerts as this shared user and add multiple subscribers to it.
2. Can I customize the text of email alerts and reference pieces of the events within them? - Yes you can Edit an alert , you will need to save it to user space and then Edit alert query , this will be visible to you only. You can enable a content pack alert without saving to your user space and then Edit alert query to tailor to your needs as well.
3. Can I send an alert notification to vRealize Orchestrator? - No you can't but we can send it to vRealize Operations Manager
Hope this helps.