Thank you Ana,
24 hours after posting my message and fooling around in Pentaho, I've realized I was focussing on the original structure for my validation (mySQL, 1 row per meta I need) when after all my transformations to produce CSV, they'd be all lined up in columns ready for my output (easy to validate with the transformation you offered).
I was initially thinking to validate my values before running my CSV Generator output and the format they were on was mainly related to my request.