Howdy!

I had a similar problem. Firstly, Peltar appears in his tower at the "castle" at night. Go behind the house and above that weird geometrical garden they like to use in Beregost (looks like a square with triangle wedges in it). You can enter the tower. Note -- lots of nice stuff if you go in there when Peltar is gone during the day.

For some reason, my game wasn't spawning Ravella, the guard who was assigned to watch over the corpse of the thief they hanged. Don't know why -- I don't know enough about WeiDU or modding to discover details. If you have done everything else (returned the pearl, killed Sirius, returned his journal, spoken with North gate guards) and you still can't find Ravella after waiting 24 game hours, you might try this.

In Area BH0300 (the one with the Temple), activate the CLUA Console by hitting <Ctrl>-<Space>. If your quick bar doesn't turn into a window with a cursor for typing text, you first need to turn cheats on in your Baldur.ini.

Once you get the window, enter these two commands exactly as I type them here:

CLUAConsole:SetGlobal("BHHandGrave","GLOBAL","1")
CLUAConsole:CreateCreature("bhravela")

Ravella should appear near you and come over to start talking. As soon as she does this, the game will save and you'll see a cut scene followed by some dialog.

Good luck!