"Counter: Give to Rydia, Edge, Cecil. Kain will be jumping, and Rosa doesn't have a consistent strong option to counter with. Also, these characters get Draw Attacks because it makes so much sense with Counter."
Rosa can counter with arrows, which are better than Edge's attack since they automatically include the Reach ability and can give status effects. If Rosa Counters with Aim and the Artemis Bow, you will end up doing more damage than Edge.
But I gave Counter to Edge anyway, turning him into a backup tank (crappier than Rydia), because I don't really want Rosa taking hits - I need her to ability slots for more important things like healing and Twincast. I don't want to leave Edge totally useless.
>is there a consensus on which is better? > 2 Braces, 3 Bardsongs > 3 Braces, 2 Bardsongs
It's subjective and hard to choose. I think Bardsong is overall more valuable than Reach, which is overall slightly better than Brace.
It is possible to use 3 Bardsongs at once, even when maxed out. If you are wearing cursed rings you can derive a marginal benefit from Hero's Rime. But this scenario is kind of a stretch. Really, Hastemarch and Life's Anthem are the worthwhile songs.
It's also possible to use 3 Braces at once, but having three tanks isn't very effective either. I do not Brace in any battle except Proto-Babil, and there, 2 is plenty (for me it's Rydia and Rosa - with Kain and Cecil focusing and Edge stealing, blessing, crying, hiding, etc. Usually Rosa is healing and not even bracing). Brace is nice until you realize it slows you down to use it - it does not work instantaneously like Defend. If Rosa is about to Brace when you suddenly realize you need her to heal, you are kind of screwed. Brace is not much use when battling Flan Princesses, for example; whom with 99 INT you can kill with 1 Counter Stardust but it's impossible to Brace against them in time before you receive multiple hits.
Note that Bardsong works better with Fast Talker, of which you may have three, but it's hard to justify distributing them that way exactly. Some people give Kain Bardsong just so he has a (pointless) magic menu.