You do need a lookup query to use in WF or Forms in order to actually retrieve any data from your lookup table. What I have done in these cases is add all columns as outputs so the invoker can determine which fields it wants to use. The issue is really in the "where" clauses of the rules, lookup rules right now do not have optional parameters so if you query by employee id in one form, and employee id and email in another you will need two rules.

That being said, we have a feature in beta right now that allows you to use the Laserfiche API to query lookup tables from JS in forms designed with the new form designer. If these forms are using the new designer would you be interested in joining the beta for this feature?

We are currently looking into 

1. Having "simple rules" configurable from the lookup rules page without requiring a lookup rule
2. Being able to have optional parameters or actually add additional where clause parameters when configuring the lookup rule

If you could provide one or two examples of lookup queries that are very close but require two unique rules, that will help our discovery process. Thank you!