By participating-in-economy, you mean things that show up in the colony's resource outputs on the overview? Do you mean to say that no matter how much lobster I send to a planet that has a deficit of luxury goods the lobster can affect the price curve but never solve a luxury goods shortage? So even if cloned organs were made legal selling them could never solve a harvested organs shortage?
AFAIK this is indeed the case for both lobster and cloned organs.
Albeit the two cases are somewhat different, as lobsters are non-econ commodities and don't show up in the colony commodity list, while cloned organs are econ commodities and shown in the panel, which causes weird bugs as shown
here.
(random fun fact: cloned organs actually use the luxury good demand class, not harvested organs)
This is an aside, but would it be possible to make a script so that cloned organs are like lobster but their value is pegged to the distance from the nearest Medical Clinic? Because that's really what I have in mind here: more sub-categories of goods that can have differing legality placed on them and that exist as opportunities for the player and not necessarily a cog in the greater economy.
You can manipulate player-facing prices for specific goods (code snippet from Nexerelin's rebellions below). I don't know if it's possible to change their 'market value' for monthly colony exports.
market.getCommodityData(Commodities.MARINES).getPlayerSupplyPriceMod().modifyMult(modId, priceMult, desc);