Overall like your post, but a couple things:
1) If any of Kulich/Rosen/Krebs/Rousek comes into camp and earns their way onto the team, that doesn't mean that the team isn't "good". Just pick any one of those guys and imagine they have a great developmental summer, really work on whatever their weakness is, and they come in guns a'blazin', a'la Derek Roy way back when. I'm not keeping them off the team just because they're young.
2) I don't think Krebs ever becomes a better 4C option than Lafferty; much more likely Krebs goes to W than Sam.