TT info yet?

All I know so far is that Laegjarn is the reward unit. I haven't heard any news on seals and bonus units yet.

NY corrin should be there at least

According to datamine, seals are Threaten Res, Spur Def/Res, and Atk/Spd Bond... not bad at all.

Worry not, chances are you already have at least one Bonus unit. OG Fjorm and Eir are bonus units.