to open the request in modify mode after submit you have to create an active link with an open window action.
1. action open window; windowtype=modify;qual: $Request ID$ = 'Request ID')
2. close window -> to close form in submit mode
active links has to fire after submit.
second question I can´t understand.
You can search the GUID field, which I assume is hidden, from the advance query bar. For the GUID used in Incident I would use the query -
'InstanceId' = "ID0050560C63F2j#K2RAIM5vCwhjQC"
Although were you would ever use this in reality is beyond me. Generally the GUID is kept hidden and not referenced in any interface with the user, only in system interactions is it used.