If we trade down we’re definitely not getting Byram

Surprisingly not a trade down post

Yes, because a rebuilding team would trade away their 1st round pick.

In return for this years first round pick

Turns out I can't read.

Please look at Detroit's defense. With Kronwall most likely coming back so he can get to 1000 games played. That means all six D we had last year coming back and that's not counting Hronek, Cholowski and Hicketts in Grand Rapids. So I seriously doubt Detroit makes a trade that brings Seabrook to the Wings. Plus Seabrook is 34 and doesn't fit in to Detroit's rebuild at all. Now I'm sure there plenty of teams that would like to have Seabrook but Detroit isn't one of them. Where Detroit is now in the stage of their rebuild Seabrook just doesn't have a lot of value for Detroit.
Since Mitchell already announced he's going back to Denver for his Junior year and that puts him one season closer to being able to choose where he wants to play. There is just too much risk for him to be seen as an asset.

With Yzerman running things now I can't see him trading that pick unless the return is colossal.