Without seeing Lamson in live action, apart from practice, does the staff know enough about what they might have in Lamson? If that answer is yes, then maybe they don't pursue a portal QB. I would hope that Dino learned his lesson with DeVito. You never really know what you have until the "bullets" are real, IMO.
As for Morgan, my no inside knowledge wild guess would be that not seeing him take a snap in those last 3 games, given how ineffective GS was, gives us one indication of the staff's view of his potential.