IMO, the Habs will draft Demidov at 5 if available, or move up to draft him, if a trading partner and a reasonable price can be found. He is a unique talent, and they will take the chance that his game translates to the NHL.
Outside of these things happening, you can take it to the bank that Iginla will be the pick. Anything else that you are hearing is misinformation, likely put out by the Habs to create a fog-like situation around their preference. The Habs don't particularly need a center; they traded for Dach and they clearly like him in the middle of the ice. They are looking for a scorer than can thrive under the pressure of the Montreal market. They are looking for character and an all-around player committed to playing a team-like game involving sacrifice, smart and physical abilities. They are looking for a player who can raise their game in the big moments. Iginla is the only player that check all these boxes IMO, especially the very important one regarding dealing with the Montreal market. I don't see maturity/smart when I hear Sennecke talks, and Lindstrom's physical gifts are clouding many people's judgment.