How are there kandra and koloss? Kandra especially, since they did their "mass suicide" thing at the end of the original trilogy.
The nice thing about the kandra for me in the narrative was that, though removing their spikes turns them feral, you can always stick those spikes back in. TenSoon feared that this was the end of his people, and it could have been, if those spikes hadn't gone back in quickly. As it was, there were costs. Time spent without spikes causes a kandra's memories to deteriorate, and some that were left a relatively long time were essentially reborn as new people. But the race survived, even if it is unlikely that their numbers will be added to.
Did TenSoon survive, then (as the TenSoon who experienced growth under Vin)?
Yes, though he did lose some things.