The documentation that you found was Version 2.1, we have Version 2.6 documentation out now, it is continually being updated with more information every day and you will find it more up to date. The lookup display types are currently in progress of being documented.
I have provided a couple of links for you that maybe of help for now.
Can you please take a look at these two links and see if they will help your scenario for a _LookupQuery.
The essence of it is you use a _LookupQuery display type, choose the query and the query at a minimum has to return the primary key and a visible value which is what you will see in the lookup.