Yes, that would be the best way to do it. I might be able to help set up a call-out to places like r/TMSFE, r/FireEmblem and r/FireEmblemWarriors if you give me a place where they can direct their findings. Maybe send them a Discord link or something so you can relay what you want to them directly without having to go through a middle man like me.
I'm most obviously interested in helping out for TMS, but I don't imagine that Encore is going to completely overhaul every piece of dialogue, down to the topic and npc dialogue. I'm thinking we could make a start to the script using the vanilla version, and then simply compare it to the script of encore, adding in any extra lines that are new. Obviously there's quite a bit of logistics to get through with that plan, but it's a start.
Anyway, if it sounds good to you, sending me a detailed outline of what's needed from TMS would be most beneficial for getting this done, so people know what to look for.