Super Hiro is out now under bag code 29, and there's no rarity as of yet with any of the Minis. You might just be having bad luck.
Also, I hate to promote things I write on but there are wikias which have a lot on the main toys ranges. They're not perfect yet and some of them still have a long way to go but here are just some of them:
www.thomastrackmaster.wikia.com
www.thomastakenplay.wikia.com
www.thomaswoodenrailway.wikia.com
www.thomasminis.wikia.com
Also, I hate to promote things I write on but there are wikias which have a lot on the main toys ranges. They're not perfect yet and some of them still have a long way to go but here are just some of them:
www.thomastrackmaster.wikia.com
www.thomastakenplay.wikia.com
www.thomaswoodenrailway.wikia.com
www.thomasminis.wikia.com