Are EventBridge events (fully) passed to Glue Workflows?

I'm not sure I understand your question. Did you follow the instructions here?

https://docs.aws.amazon.com/glue/latest/dg/starting-workflow-eventbridge.html

There is no native option to pass EventBridge event details to Glue job. But I used the following workaround to do this:

1. You need to get an event ID from Glue workflow properties

event_id = glue_client.get_workflow_run_properties(Name=self.args['WORKFLOW_NAME'],
                       RunId=self.args['WORKFLOW_RUN_ID'])['RunProperties']['aws:eventIds'][1:-1]

2. Get all NotifyEvent events for the last several minutes. It's up to you to decide how much time can pass between the workflow start and your job start.

response = event_client.lookup_events(LookupAttributes=[{'AttributeKey': 'EventName',
                                                         'AttributeValue': 'NotifyEvent'}],
                                                         StartTime=(datetime.datetime.now() - datetime.timedelta(minutes=5)),
                                                         EndTime=datetime.datetime.now())['Events']

3. Check which event has an enclosed event with the event ID we get from Glue workflow.

for i in range(len(response)):
      event_payload = json.loads(response[i]['CloudTrailEvent'])['requestParameters']['eventPayload']
      if event_payload['eventId'] == event_id:
                event = json.loads(event_payload['eventBody'])

In the event variable you get the full content of the event that triggered Glue workflow.