I think you're being a little paranoid on the injury front. When's the last time a team lost 2 rookies due to injury in the same season? As long as Vegas doesn't sign Happy Gilmore, I think we'll be fine.
The PMD thing is a good point though and this helps me understand your projects a lot better. While I actually don't think its that hard to score on a bad team (hello Mikael Granlund), I hadn't thought about how the Sharks' lack of PMD would effect the forwards. The age point about Celebrini is a good one too. I keep forgetting just how young he is.
Before reading your post, I would have been happy if Smith/Celebrini each hit 50 pts and hoped for Smith to get 60 (call me crazy but his NCAA season last year really has me with high hopes). Now, I'll say I'd be thrilled with Smith hitting 50 and Celebrini hitting 40. Look at what you've done to me.