Should be perfectly fine. One of the mods in fact plays Lightning - whose story is awaiting a third game installment of which she's the star character. That's one of a number of canons which aren't yet complete, so you'd be fine.

As characters regain their pasts piece by piece, you'd have plenty of room for the rest of the story as it's released. Suzaku here has been in the game for a handful of months and still has plenty to echo back. The pace of that is also entirely up to you.

Are there any other questions I can help you with?