I'll second Toadhill's point about overwatering being just as bad as underwatering. I've been guilty of both. And yes, it's sometimes harder to know when you are overwatering, especially on spruces and pines. Most of the time I know when I'm guilty of underwatering.
I've had folks a lot smarter than me tell me that if you planted a bare root tree, a 1" caliper tree, a 2" caliper tree, and a 3" caliper tree all at the same time, that they will often all be the same height in 10 years due to transplant shock. Ask me in 10 years if my experience bears that out, but after planting all the above, what I know for sure is that I loose far fewer small trees than the large impact specimens. And the small trees are a lot easier on the wallet, and allow me to plant more of them. But it's still nice to get the immediate impact from the larger trees.
Also, I'm just about ready to quit trying to plant non native trees-too many problems with diseases and bagworms. I just made a trip to our county extension office with branches from one of our spruces to try to find out what is causing the needles to fall off.
Regarding the OP's pictures, the leaves look to me like a classic case of transplant shock, and if so, the tree will take care of itself by dropping off the dead ones
in due time. My experience is that it may be best to wait till next spring to see for sure what trees or branches are dead.