I've personally had bad experiences with using topsoil -- one of the kinds I bought for my ball python's bioactive enclosure ended up having manure in it, and it gave us issues with scale rot. Would like to avoid that if at all possible. I'm not currently wanting to move Inej to bioactive; that'll likely be something I do for her adult enclosure, not now. I think peat moss would also pose a similar problem as the coco coir she's on now, therein it would be very dusty. I do use it for my bioactive mixes, but that's a different story. Thank you for the suggestions.
I did buy a different kind of substrate today, a bit more chippy. I personally don't worry about impaction, as my temperatures seem to be ideal for digestion. I've always fed in the enclosure with no issues and a fair amount of dirt getting on feeders without problem.