I hope I'm not telling anyone how to suck eggs but the DMG has always been a good place to look to see additional guidance on some spells. From page 41.
Augury: This is a general future determinant with only a half hour maximum, so you (meaning the DM) need not be too exacting with regard to your vagueness. When the augury is cast, simply compare the knowledge you have and give the character general impressions of the question asked. "Will we do well if we venture onto the third level?" Answer: "Those who survive will be rich!" Basis: You have a terrible troll near where the character will enter the level (if he does), but the probable party is strong enough to beat it after a hard fight, and the monster guards 10,000silver pieces and a +1 shield.
Bruno:
"If we reenter the barrow in which our friends were slain would the creatures we fought before be more strong or less strong."
You run the danger here of the Augury coming back with the simple answer 'yes' Bruno and then you've only grown wiser in regards to how not to ask the question.
Perhaps something like, "Will the power of undead we face if we reenter the barrow have increased?"
Best of luck to you!