OK, I think you want to provide name instead of integer value for a volume user or group ID, and netither WFA nor OCUM cache this name/id information from ONTAP.
I don't think changing dictionary entry / command would solve this problem.
To workaround this, we should first get the existing user name to id mapping information from ONTAP using 'unix-user show -vserver' CLI command, and then provide that mapping information in the workflow user input query for $userid parameter.
e.g.: In your workflow, change the $userid parameter type from String to Query and provide the name to ID mapping information in the query like shown below. This way you will always know the name and id for the user/group while creating the volume.
SELECT
"0" AS "User_id",
"root" AS "User_name"
Union
SELECT
"65535" AS "User_id",
"nobody" AS "User_name"
union
SELECT
"65534" AS "User_id",
"pcuser" AS "User_name"