Lots to unpack here... first of all, poor Finn. That scene with Quan and Ethlyn made me tear up a bit.
On another note, please don't marry your cousin Shannan! Fun fact, in my first FE4 run, Shannan really did almost end up with Larcei. I tried to set her up with Ced instead, and then somehow Johan swept her off her feet, the absolute mad lad. It was a whirlwind romance. That didn't help me much, because honestly, the axe bros are not very good (sorry guys).