Consensus says there is definitely separation between Lafreniere and the rest. There are probably 3 or 4 guys that could go first had it not been the Lafreniere draft. Byfield has been the consensus #2 for a while, and I'm not convinced there is a single person out there who would choose Byfield at #1.
Only time could tell how distant the 2-4 group will be. Lafreneie is one of those players who will likely make an immediate NHL impact at 18 years old. Others may take a year or two. So while some of these players may close that gap over the years, Lafreneiere will be in the league earlier and become an impact NHL player at a younger age.
A good comparison is McDavid and Eichel. For the record, I'm not saying Lafreniere will be McDavid level. But McDavid was a great NHL player immediately. He was scoring more than a point per game as an 18 year old. Eichel hit a point per game level in his fourth season, so it took him a bit of time to start to dominate at this level, as most high end players do. So while both are great players, there was a big gap early on, Eichel has certainly narrowed said gap since. Of course, there is still no doubt McDavid is in a league of his own.
In the end, only time will tell.