Trades and Specialties help?

Oh no- I was asking here to make entirely sure I was thinking everything right! Another site I used to be on had things like this, so I needed to make sure I wasn't mixing things up! I think the guidebook is alright the way it is unless staff wanted to edit it to add on ways one could mention things to get each one(though its pretty obvious how). 
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So theoretically I could just go through and have him notice things every thread? Weakness of others, or make plans for things etc? That actually sounds a lot easier than i thought. For that, would I have to do 5 threads going for tactician specifically, or would i have to get him into Mercenary first somehow?