Agreed. Harrison has always made sense for this team, and if they can get him for very little due to his price tag, then go for it. Yes, $10m is a lot for a utility infielder, but chances are he will get 500-600 plate appearances due to how injury prone the middle infield is, and likely if/when JD has to miss a little time as well (he is getting older as well). If you can get a ~2 WAR out of him and not have to give up much, then you can do a lot worse. Plus he has two team options for '19 and '20, so if you want a stop gap 3B to bridge to Vladdy, then he's your guy.
I could see a scenario where they add Harrison, and move Pearce in a separate deal (if he's not starting at Dh or 1b then he's kind of pointless to have around). I'd prefer they move Morales and start Pearce at DH, but no team in their right mind will trade for Kendrys.