I have no real advice to give on the Adept III version, as I don't have one myself to comment on it's power. What I can comment on however, is the Tellurian Hero. Something has to be wrong with this spell. Not in a bad way.
This pet, as I'm sure you've noticed, is absolutely ridiculously strong. It tanks superior to most actual tanks I've grouped with, and it's damage output is ludicrous compared to the other versions of the pets I've used. I figure, if it isn't broken, don't fix it, hehe. I would say try and get rid of the Tellurian Veteran, as that will rake in loads of cash on the market if you can sell it, but it may be difficult to find a buyer, simply because of the presence of the Tellurian Hero.
Personally, I'm not investing the Tellurian Veteran Adept III until I'm able to get it myself. I won't be buying it off of the market. Until then, enjoy the free massive power of the Tellurian Hero while you can, because I can forsee it's strength being changed eventually.
Klarth, 24 Conjuror of Antonia Bayle.