I don’t have personal experience as a grower, but would paper waste be an adequate substrate? The particle size would have to be small, but does bedding just have to be a place to hide and stay dry?
The feed question is an interesting one. I think sesame is a good seed for oleic acids.
“The fatty acid composition in sesame seeds consists of abundant unsaturated fatty acids: oleic (35.9–42.3%) and linoleic (41.5–47.9%) acids from 80% of total fatty acids; less than 20% are saturated fatty acids, mainly palmitic (7.9–12%) and stearic acids (4.8–6.1%) [2].”
https://www.mdpi.com/2073-4395/9/12/801
I think that sesame paste could be combined with veg waste and either dehydrated and mixed as a slurry for feeding, or frozen and thawed.
I think mushrooms, microgreens and mealworms are the perfect trio. Spent mushroom substrate and microgreen roots mixed with some sesame for healthy fatty acids make the systems link up elegantly.