IMO, after thinking it over, I feel Izo and Asura's deaths work well, because they both had the most regrets, and the most people to meet in the afterlife.
Izo lost not only Oden without being there to do anything about it, he also watched Ace, a brother to him, and Whitebeard, just as much of a father to him as Oden was, die in front of him.
Asura not only fell back into his bandit ways and became a sad shell of his former self, it was because he couldn't stop his men from planning a failed suicidal raid on Onigashima, despite knowing they had no chance.
Out of all the Scabbards, Izo and Asura honestly have the most regrets, and most tragic deaths associated with them. I hope they can find peace in the afterlife with Oden, Whitebeard, Ace, and the other Samurai lost to Kaido and Orochi. They deserve to see their Nakama again.