Dragons yes, not Drak’thyr though. The lore was that dragons and dragonkin are limited to just one aspect power (dream, life, earth, time, arcane), however out of nowhere we learn that actually Deathwing already had cracked the code and was able to create a species of dragonkin that could use all 5.
This is not so far fetched as someone playing a musical instrument and discovering a brand new source of magic because X event happened.
Yes, bards in most IP’s that have them are spellcasters but they use music to cast their spells.
Idk how a tank bard would look like, but by DPS I would assume they mean something like an Augmentation evoker, which is a support spec but because the game is still using the holly trinity model (tank/heal/dps) the spec is considered a DPS spec.