Ok this is how I would setup an NPC like that...
All of the entries I would set to "DependsOn" -2. Except for the reward entry which would depend on -1.
For the Condition field of the reward entry, you would have
GETONCARRIED,nameofquestbook,questholder,iscompleted=true
In the notriggeroncarried field right at the top of the Gump i put the name of the quest book, aswell as the attachment like so
Name of the quest | ATTACHMENT,name of the quest,XmlQuestAttachment
This means that the NPC will not give the player 2 of the same quest books, and will not let the player do the quest again if he has the attachment
Otherwise you could add the quest attachment into the Condition field if you only want it to apply to that entry like so:
GETONTRIGMOB,[ATTACHMENT,XmlQuestAttachment,name of quest,visible]=false
and i'm not too sure about displaying the NextRepeatable thing