As the 247 site explains, "Five-stars (98-110 rating): The top 32 players in the country to mirror the 32 first round picks in the NFL Draft. These are the 32 players that we believe are the most likely to be drafted in the first round from each recruiting class. Any player with a rating of more than 100 is considered a "franchise player" and one that does not come around in every recruiting class. (Jadeveon Clowney is the highest-graded player in the history of 247Sports and he received a 105 grade. Bryce Young and Jeremiah Smith received grades of 101.)"
In other words, if Demin were only rated at the level of On3, that would mean that 247 projects he won't be drafted until the end of the first round/beginning of the second round. A five star player with a rating of 98 or higher means first round projection. If Demin is a top 15 pick projection, he would have to be in the 15 range. Interestingly, as of now, 247 only has 18 players with a 98 rating/five stars. I don't know if they think this class is weak, or if they already anticipate slotting a number of international players in that will take up the other 14 five-star slots. Unless 247 rates Demin much lower than the draft sites, I can't imagine he won't be top 20 and a five star player. The drafts sites I looked at had Demin going 7th, 6th, 9th, top 14 (but not rank-ordered). Thumbs down goes out to Bleacher Report, which didn't even mention Demin for the first round, and apparently doesn't know who he is?? Maybe On3 used Bleacher Report to make its rating for Demin?