I don't think this has anything to do with SharePoint.
The correct way to get the "value" of a checkbox (i.e. whether it is checked or not) using jQuery is
$('#cbAttending').prop('checked') // will output true if checked, false if unchecked
or (the older way)
You can achieve the requirement using the Workflow.
You need to add two actions.
Create List Item
Refer to the link below to send an email. Similarly you can create the list Item.
Send an Email when Item is created
You need to edit the steps in both the actions as per your requirement.