As far as Tidus' (who, although later voice-acted sidegames like Dissidia have shown that his name pronunciation in English is "Tee-dus", I will always refer to as "Tide-us" because it sounds less ridiculous to me, and appeared to have a connection to water) name going unspoken, this was still the era that allowed you to name your protagonist--although not the other party members, as in the previous games. They managed to get around that pretty well, all things considered, although if the entire cast had been manually name-able, it would've been pretty awkward dialogue wise.
On a related side note, I always used the 'default' names as I felt like it was a part of the narrative, so this was no big deal for me. But the newfound inability to name everyone was something of a controversy at the time, as was voice-acting in general. I remember a particular post by a longtime series fan, describing how he was British, always named the protagonist after himself, and imagined him to speak in the same accent that he did. Suddenly, a *gasp* American accent came booming out of his speakers, and he felt his connection to the character was broken. Seems quaint now, but interesting.
Wakka is inherently ridiculous. It only makes sense that he would fight using something like a ball, we're lucky they didn't make him a fucking juggler.
I think the only 'in-universe' attempt at an explanation for the underwater breathing is that "Blitzball players totally like, um, master the art of holding their breath, for like, uh, super extended godlike periods of time, and stuff". But then...aren't there parts later where non-athlete members of the cast do the same thing? Yeah, it doesn't hold up. Magic.
