Herb Jordan. Frank McGee was more prolific as was Marty Walsh,pre NHA. Hod Stuart was a defenseman. The HHOF tends to recognize the early greats whose careers were cut short, rightly or wrongly, plus Jordan simply did not cut it in the NHA. So basically you have zero team success, not as prolific as McGee, Walsh and Bowie with a quick exit from the NHA at an age where he should have been in his prime.
Ed Oatman. Difference maker in his situation was attacking a referee, Mickey Ion in 1920.Given the influence Mickey Ion had in hockey and the HHOF, not an easy hurdle to overcome.
Bernie Morris. 1917 playoffs, WWI, his only worthwhile playoffs. Rest were weak. Harry Oliver was mentioned because he had a bit of a bounce back season playing with Oliver in Calgary.Foyston had a more consistent playoff record, longer career with success in the NHA.
Re: Jordan, you're assuming he couldn't cut it in the NHA but his 9 goals in 6 games in the 1910 season suggest otherwise. He was dropped to make way for newsy Lalonde, which I'm sure you'll agree was nothing to be ashamed of. He was finished very young but I haven't read any evidence that it was because he "couldn't cut it", and it still doesn't make him any different from a number of HHOF stars.
McGee may or may not have been more prolific but McGee is a highly revered early superstar and is not the benchmark for induction. Besides, when you analyze their careers during the four-year period that McGee played top-level hockey, it's quite debatable who was more prolific.
In 1903, McGee finished 2nd in the CAHL, one point ahead of Jordan, both comfortably behind Bowie.
In 1904, McGee only played 4 games but his per-game average would have given him 19-20 points if he played 6 games like Jordan. Jordan had 25 points. If he had played 8 games like Bowie did, he projected to 33 points, 3 more than Bowie.
In 1905, Ottawa moved to the much less competitive FAHL. McGee tied with Jack Marshall to lead the circuit with 17 points. Jordan was over in the much better CAHL, finishing 3rd behind Bowie and Joe Power.
1906 is the only season in which you could say McGee was clearly more prolific. He finished with 27 points, 3rd in the ECAHA. Jordan was 9th with 19.
Jordan actually had more points during this time and did not take a one-year vacation in an easier league so I wonder why you would say he was not as prolific as McGee. Then of course, after these four seasons I have gone over, Jordan had three more very productive seasons (3rd per game, 4th, 2nd in the EC(A)HA in 1907, 1908, 1909). McGee's regular season career doesn't touch his.
I'll accept your answer about Oatman to say "OK, sure, he might have been a good enough player, but other factors kept him out" - good enough for me.
Re: Morris. 13 points in 18 other playoff games doesn't exactly qualify as "weak". As for 1917, you'll need to show us how WW1 made this less impressive. Who did he avoid playing in the playoffs? Whose absence or presence made it too easy on him to pot all those goals? Harry Oliver was in his prime in 1924, and Morris was well past his. Bounceback year or not, that was not among Morris' best seven seasons. Foyston does have an excellent playoff record, no disputing that.