How to make the second field of a cascading as a user picker

[Salih Zengin]

Did u resolve this anyway?

[Nic Brough -Adaptavist-]

A cascading select is a single field with two selectable inputs.  It's not two fields.

So, you'll need to write a new field type to do that. 

Or, if you're on Server, you might be able to use Script Runner behaviours (or possibly javascript) to make a pair of separate fields interact (select list and user picker).