Harken wasn't in the initial ranking phase for the Split Path reason, same as Karel and Geitz. Wallace wasn't ranked cause of the whole "yes, he's forced in Lyn mode, but his worth there is so much different than his worth if you get him later!" Not to mention he changes dramatically if you play Lyn Hard (which is the same as Lyn Normal, just no tutorial, so its not quite the same as Eliwood/Hector Hard which are actual changes) since he suddenly gains more levels to play with (no forced level 12 Promotion or whatever it was.)
Farina wasn't ranked cause of the "Hector Mode" only thing. Karla is the most obscure PC in the game, requiring not only Hector mode, IIRC, but also to raise Bartre to a specific level.
I think that covers all the rankable PCs that didn't get ranked (as in, Nilisinian go without saying.) After FE7 proved it was a strong rank in the DL, it went up again with the FWs. They got shot down, granted, cause people really didn't want to just see "More characters with different stats who bring nothing new to the DL." (Frankly, its true, unless you allow Initial Equips, then at least Harken brings a Brave Sword!)
In...the end, FE7 ended up basically showing "Rank all PCs just cause you can!" even if its a strong ranking isn't always the best idea. The way we handled FE8, barring some odd choices (Why Garcia and not Ross for example.)
In any event, the point is, those specific PCs you mentioned were not innitially hyped for ranking until after FE7 proved that it had a vote draw strong enough to possibly overcome that, and even then, the PCs got shot down in the second stage.