I believe your original question…
same resource repeating ie same ids being returned
…is because you’re both preloading and left_joining the same tables in the same query. It looks like you could delete your joins (leaving your specifically-queried preloads) and stop getting duplicate records.
As for what gets returned, if it were me, I’d just drop the select statement. Preloading will return the associations, and I’d move forward. Perhaps there are business-reasons you strongly prefer to bang your head against nested select syntax to return only 3 fields alongside associations. I wouldn’t choose to bang my head against select syntax when I could just filter out fields in Elixir, but that’s me. 
