The
DKS FAQ/Guide contains sections on bonus skill and stat points. There are a couple forum topics for D2:ED listing skill/stat books and mindreads, but I don't recall if there are any for DKS (minor changes were made).
There is some discussion of stats and skills in the topic
Anyone help a newb with Warrior build ... ???, and even a bit on rangers.
As Melianos said, you can only build (and upgrade) one creature, so you only need to keep the best of each type of part you find. I kept a list of my best parts handy, so I could sell any lower quality ones before talking to a necromancer, to help keep the part list from getting too cluttered.
You can have the creature active as well as one summon, though.
If you want a fighter summon, the demon is better than the undead, once you meet the level requirement. The ghost can heal you (though not necessarily exactly when you want it to) or cast fireballs at opponents.
