How would one make it possible to add organics to any planet including ice giants?
You would need to edit the terraforming_options.csv file directly for that, its found in modname/data/campaign/terraforming_options.csv from there you need to edit the row canChangeGasGiants to true for every row with content.
Unfortunately despite having done that when I try to give ice giants organics when the project finishes nothing is added, I'll see if anything shows up in the logs with a greatly reduced selection of mods later.
Addition: Nothing useful in the log, all it says is "
1149491 [Thread-3] INFO terraformingmadeeasy.industries.TMEBaseIndustry - Completed Adding Plentiful Organics condition in Uranus by TME - Mineral Replicator", but nothing was actually added, it works just fine on habitable planets though.