If you read the Fair Play Brochure linked from the Fair Play policy, you will see more detailed sections covering "Attempted Association" and "Product Copying". The reason you're not seeing an explicit "commercial use" call out is because there isn't one - if you want to use their trademarks commercially, you will need to get a commercial license via a licencing agreement:
The LEGO Group’s trademarks and copyrighted material may NEVER be used by unrelated third parties for their own commercial or marketing purposes, unless formal permission or a written licence has been granted by the LEGO Group.
Basically, you should not use the LEGO logo anywhere on your product or marketing materials to avoid any doubt. I'm aware of at least one LEGO Certified Professional (whose main site seems to have dropped off the net, but you can still find some bits on Facebook) whose products you can still find listed on various sites that give a fairly good example of how to do this:
I've seen these in Aquatics shops and online. A number of the listings mention LEGO but there's nothing explicit on the packaging - although the blue 4x2 is rather close to the official red 4x2 that is copyrighted. The catalogues however do carry the Logo as part of the LEGO Certified Professional program.
I would recommend doing point 1 below, as I'm not a lawyer, but I would suggest your options are either:
- Not referencing LEGO in any way, other than through the product shots.
- If you do reference LEGO, that should be purely in text ideally on the rear of the packaging (i.e. not prominent), include the ® symbol, and include their disclaimer (i.e. "LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this product") and contact a lawyer.