All the stones, and the Orchiata would last for several years for sure, polystyrene of course, charcoal, it can make some problems after a while depending on the wood used. Tree fern, definitely fine too...
In my earlier experiments with Orchiata, I repotted some hangianum in 30 Orchiata Power (9-12 mm) + 4 pumice ( the grey one) + 4 polystyren beads ( the 1cm ones) + 2shredded tree fern and 1 coir, with some chemistry grade calcium carbonate added. They got nutricote every 4 months, and I found out two weeks ago that I still have 50 plants in the original mix, never repotted, in a corner of the nursery. It did not decompose at all at nearly 5 years now and the plants definitely have a lot of active root tips, no dead roots or nearly so. Only the plants are grossly overgrown, so they need repotting, but I think another 1-2 years more would be absolutely possible. Therefore, it would be possible to have a mix where we can avoid repotting for several years. In fact, the plants are rarely repotted in the wild, and apart from some plants growing in moss, where the fresh moss 'renew' the growing media in some ways ( but antique roots are still alive an well, deep below), many species are at the same spot for decades, untouched. The water, nutrients, whatever, keep the media suitable seemingly forever...
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