Disclaimer: Content and opinions are my own and not the views of my employer. The software discussed here is not official Salesforce software.
Some nice Flow-related posts from the community
Terrence Chiu with a great example that incorporates both the lightning:datatable component and record:editForm.
Rich Engelhard has a two-part post that also incorporates datatable and goes into fabulous detail.
More enhancements to the Lookup Component
Eric Smith has added “default” functionality: You can enter a default value for the input field (I2_Display Which Field). When provided, it will override any WhereClause and display the default value as Placeholder text in the input field. You will still need to select the drop-down then select the single value that is displayed. If you start to overtype the input field, the default value will be cleared and the WhereClause (if provided) will be reset and the field will act like a normal filtered lookup with search. Install the updated version here.