This is a really nice guide. The section at the beginning where you explain words of power is really important; after reading this guide I am definitely thinking differently about that approach to spellcasting.
Also, I particularly liked the detailed breakdown and analysis of the words. The way you organized it was clearly better than the usual guide format. And the spell sheet at the end is a nice idea. As a bonus, great illustrations throughout. (Where did you get these?)
All in all, a really great guide!
Definitely let him do it. Wait until just after the eggs hatch (just before he can sell the birds). Then, if he is of a good alignment, have him be visited by an elder from the church. "You are a respected member of our community, so I hate to bring this up with you, but we performed an augury which predicted that you are in peril of losing your immortal soul. The augury suggested (and I assume there must be some mistake) that you would SELL YOUR OWN CHILDREN INTO SLAVERY." See what he does.
If he's playing an evil character who wouldn't mind having the church tell him that he's wrong, then he can pass by an old gypsy woman or soothsayer on the street who cries out to him: "The gods have told me to warn you . . . a most terrible misfortune will befall you if you ever SELL YOUR OWN CHILDREN INTO SLAVERY!"
Either way, the point is that it's an opportunity for interesting role playing. It gives the player a strong nudge to have his character experience a change of heart when he realizes what he is doing. But, of course, if he DOES have a change of heart, then what is he going to do with the baby Axe Beaks? A perfect adventure hook. The thing just writes itself.
Best way to play this encounter? After the first three rounds of combat, announce "Ten minutes later, just before the invisibility runs out, you manage to wipe out the last of the skeletons."
You can _always_ fudge in the player's favor when things get boring. Next time, give the barbarian a short-term single-charge antimagic token to use.
20. All you inherit is a title. Your great-uncle dies. You never knew him well -- all your life he was just a creaky old white-haired man living in a nearby town who used to grumble about how you should always remember to act your station in life. But when he dies his executor delivers a small, intricately carved wooden box to you. Inside is badly yellowed piece of vellum signed by the king's great-grandfather, granting your family the title of "Duke of Egileer" in perpetuity. There is also a gold signet ring displaying a crest with the double bars of a duke. You have never heard of "Egileer", and you have no idea what this implies, but technically you ARE your great-uncle's heir.