My quest has an NPC that gives it to yatta yatta yatta, but he comes up to the player and initiates the conversation, how can I make it so the player has to activate the npc before he mentions the quest?
Your NPC will only initiate dialogue if he has a Dialogue package. Give him either a wander or sandbox package and he won't talk to the player until activated.
And how can I customize his "random" conversations? (I am assuming random conversations means if the player walks up to the NPC and activates him?)
Because I don't want him to have the default greeting your average NPCS have.
If you want him to have a special converasation you will need to add the GREETING (it's a special topic that is capitalised) to your topic list for your quest, then write whatever you want him to say and give it the appropriate conditions.
If you want him to have 'random' conversation as in a topic that says something like "Heard any rumours lately?" you need to write all the different responses that you want him to have, then tick the 'random' box (the one below say once), for the last random topic tick 'random' and 'random end'. That way he will choose from one of the possible options at, well random.