I think those are important questions. We saw the answer to the latter question last year, the answer was yes (depending on who gets hurt). The question to the first one is no.
Follow up questions:
1) Can this team get more out of the same roster it ended with having a full season of playing together?
2) Can they add the necessary pieces to improve the team by the trade deadline this year?
Less important:
3) Would a different match up yield a different result? Carolina has killed the Islanders for years now, even when the team was going on deep playoff runs. If the team can avoid Carolina in the playoffs do they have a legitimate shot to go deep again?
The league isn't static and the same roster can put together a great season one year and then a less impressive one the next. Players take steps forward and regress, or they don't. Are there enough players on the Islanders roster who can take another step forward and be better than we saw last year? Barzal, Horvat, Dobson, Romanov, Holmstrom, and Wahlstrom are all players that could produce significantly more this upcoming season. Who might regress? Nelson, Lee, Pageau, and the fourth line are all the big ones I think. Which is more likely to happen and how does that benefit or hurt the team?