To wrap up the defense, a look at 3rd pairings:
Tikal-Owen
vs.
Buller-Randall
I think Buller did suffer from a bit of antisemitism personally, but I follow the school of thought that we can't assume he would have replicated what he did in the AHL in the NHL, and what he did in his few years in the NHL over an entire career. Buller had that one great year, but I think Tikals 2 best defensemen at WC awards, and a long national team career make him a little bit better. Tikal is probably better defensively, and Buller probably a little better offensively just because we know very little about Tikal's offense except how he compared in WC to guys like Ivanov(not as good) and Ragulin(better). Tikal bested Eduard Ivanov, Alexander Ragulin, Karel Gut, Lennart Svedberg(in 1965), Vitaly Davydov, Viktor Kuzkin, and Jan Suchy(in 1965) for his best defenseman awards. Overall, I think Tikal is the better player because of Buller's extremely short career at the highest level and Tikal's lower peak but much higher longevity against his country's best competition and performance at WCs.
That brings us to George Owen and Ken Randall, two puck movers. They played in pretty close proximity to each other.
Goals
Owen-1, 2, 5, 5, 7
Randall-2, 3, 5, 6, 7
Assists
Owen-2, 3, 3
Randall-1, 1, 2, 3, 3
Points
Owen-1, 2, 5, 8
Randall-1, 3, 3, 4, 7
So, Owen was a better goalscorer, Randall a better playmaker, and Randall a slightly better offensive defenseman overall. But as you said, in 1919, 1920, and 1921 Randall played some forward, but not very much. Unfortunately, we don't know how that may have impacted his finishes because it was so long ago. Considering this, as overall offensive players I think they're about even. People try to use the argument of "Owen didn't get all star votes and he was good offensively, so it must mean he wasn't good defensively." I call BS on that. We don't have voting records for that far back because all stars were only recorded for the last 3 years of Owen's career. For the first 4 years of all star voting, Eddie Shore, Lionel Conacher, King Clancy, Ching Johnson, and Sylvio Mantha had a monopoly on those spots. Those guys are all either legit #1s or legit #2s. Combined with the fact that there is nothing that says Owen was bad defensively, I think he is average. Randall provides more physicality, Owen was the better skater. Overall, I think they are very close to a wash.
Overall, 3rd pairings are an advantage to Philadelphia. Owen and Randall are more or less a wash, but I think Tikal is definitely better than Buller, tipping it in favor of Philadelphia.