I couldn't find anything in the archetype or the Magic chapter of the PRD or elsewhere that clarified anything about choosing targets for stuff like that, so I'm gonna say that the ability must target a different creature with each damaging sound. 10d8+50 sonic damage (assuming 20 Charisma) to one target at 10th-level (even with Fortitude saves allowed for half damage) at the cost of one measely Bardic Performance use for the day is just excessive (45+ damage even if they pass every single Fort save!). 27 times per day at 10th-level? Yeah......no.
While Synjin can deal around 80-100 damage with a full-attack action when using all his archery feats........he has to score 4 hits at an attack bonus around +4 to +10 per shot to do so, against regular AC, not touch AC. Which at these levels is typically between AC 22 and AC 30. Or he has to score a critical hit (confirmed with that lowered attack bonus from Deadly Aim and Rapid Shot) and a regular hit. He accomplishes this maybe once per battle on average, sometimes twice. And it's typically offset by the number of misses he gets when using all those feats together (though luck tends to favor him on attack rolls, so it's not entirely offset).
If the Weird Words performance had some higher cost per use it might be acceptable for its level (though the fact that sonic resistance/immunity is less common than other energy resistances/immunities, and that sonic damage ignores object hardness, makes it more advantageous than a cold-based or electricity-based attack), but as it stands.......I think not. A 10th-level Bard with Charisma of 18+ would have 2 spell slots of 4th-level. He could cast Shout twice per day for 5d6 sonic damage in a 30-foot-cone (average 17.5 damage, half on a successful Fort save)...........much weaker and much more costly to the Bard, though Shout would at least affect multiple targets (partly balanced by the fact that it has to be carefully aimed or timed to avoid catching allies in the blast). The Bard could've used his 4th-level slots to cast Dominate Person, Hold Monster, or Greater Invisibility instead of Shout, so there's a definite opportunity cost involved (10th-level Bards know 2 spells of 4th-level, so it's likely they'd know at least one of those very-useful spells). But spending 1 out of 27 Bardic Performance uses for the day to inflict a bunch of damage? That's a pittance.
So.........while Weird Words is relatively weak under my decision regarding its unclear targeting choices, at least it can be used to help mop up a bunch of weak or already-injured enemies over a few rounds, and at least it isn't overpowered this way. For the cost of 1 round worth of Bardic Performance use each time, that's about all you can expect. For a 6th-level ability, it's better than the Sound Burst spell anyway for damage output and precision (aside from the minor chance of stunning that Sound Burst has). Wordstrike deals 1d4+15 damage to a single target at 10th-level for the same cost (assuming 20 Charisma again, as a likely average for mid-level bards), which is still weak at 10th-level but also still very cheap in terms of daily resources.
As for the Wings of Flying, no, you cannot spend more than half your starting gold on a single item. You could get around this to some degree if you had the means to craft the item yourself (meeting the prerequisites, passing the appropriate skill checks, paying the item's creation cost), so long as the item's creation cost was no more than half your starting gold.
