Who'll make the team won't be just talent, but long-term development.
Putting a scoring forward on the 4th line because he can't crack the top 9 this year doesn't make sense, better to spend another year in the AHL in an offensive role. So while Leier and Laughton are 4th line canidates, Martel will face the same roadblock that kept Weal in the NHL, top 9 or bust.
In a similar fashion, if Ghost is QB of the PP, and Sanheim will be limited to a 3rd pair role with no PP duties, he might be better off in the AHL - Hextall might decide that Sanheim has to show in camp that he's ready for top 4/2nd PP duties to stick, while Hagg and Morin merely have to show they're ready for 3rd pair duties and PK.
However, if players show they're ready, Hextall will go with 3 rookie defensemen without hesitation - he kept Konency over Leier and AK and Laughton last year. Konency showed he was ready for top 9 duties, though they did limit his minutes and his responsibilities.
The difference this year is there's enough depth that Hextall doesn't have to force the issue just to fill out the roster, but he's not "conservative" in the sense of reluctance to play rookies, he's "conservative" in the sense of erring on the side of caution when it comes to rushing players to the NHL.