If I were in his situation, I would rather someone be honest and upfront with me than not say anything and later on I struggle and have issues.
Together with all the posts, I think he has some good info and now has the option to either use the Culterra for chillies and get other soil for his cannabis or to try and make it work - so now it is ultimately up to him.
I can see that if you had ended up with Culterra soil, you'd try and use it and make it work.
I on the other hand would scrap it and get something else, nothing wrong with either approach. As long as we both get cannabis in the end
I actually had some Culterra germination mix, I tried it but disliked it and gave it away. Was more like river sand. I have received rooted cuttings in Culterra soil and they went light green very quickly even with usual feeding and once I repotted into the OM soil I had at the time they were nice and dark green within 2 or 3 days.
Soil makes quite a big difference. I think it was either you or perhaps @trichomechaser who created a thread or posts about which soils to avoid and the bark etc?
That Culterra soil is like R34 for 30L from Builders, not too expensive and if he can repurpose it for chillies and save himself from possible issues later down the line, it sounds like a better plan to me.
Freedom Farm soil also has Fungus Gnats. I have struggled to get rid of them in my grow. They're super annoying.
Organics Matter soil has worms, which is a good thing. I have seen worms in my OM soil on multiple occasions.