EDIT:
1.) Monument to Perfection (replaces the regular monument)- Standard monument but allows one citizen to become a bard.
2.) College: (replaces Library)- +20%

,+20%

, allows one citizen to become bard, allows one citizen to become sage.
3.) Festival: (replaces Market)- +3

, -1

allows one bard, allows one sage.
These UBs should cost extra to build as they should simply be better than what they are replacing.
I'd have to disagree that these are better.
You have to keep in mind that culture is a largely irrelevant mechanic. Beyond the initial culture to get a city going, you can just never look at it again and not care.
Therefore, a monument that allows a free bard, is at best, meh. It could actually be a bad thing as the AI governor likes to assign specialists automatically, and I don't want artists corrupting my GP pool.
I'm pretty sure Dural already have a "college" building, and it's better than what you described here. A base library gives +25% research by the way, so this is actually weaker than a normal library. Again, the extra culture and sage slot are largely irrelevant.
The festival, is horrible. A market without the merchant slots is a bad idea. Merchants are a rare enough GP type as it is, and a market is critical if you need to get an early merchant to found a guild.
In general, I'd say steer away from culture/bard bonuses, because they're pretty worthless. Bards are already just about the easiest type of GP to get, and also the single least useful.
Focus more on Engineers for Dural, which are pitifully rare for most civs. Representing the quality of their craftsmanship and industrial achievements.
Oh, also, just putting "Dural" in front of things, like Dural Market and Dural Courthouse, is horribly bland and uninventive. Put some effort into coming up with nice names. The point is to distinguish the dural more, and add to their uniqueness. Giving them bland things won't help
Some random name ideas:
Market - Trade Hub, Bazaar, Merchant Pavillion, Exposition, Fete
Elder Council - City Council, Council Chambers, Mayor's Office, Assembly
Library - University, Hall of Learning, Athenaeum, Biblioteca
Courthouse: Magistrate, Seat of Judgement, Administratorium, Cloister
Carnival: Circus, Bacchanal, Fiesta, Saturnalia
If you have no imagination, just go use a thesaurus, and broaden your vocabulary. Put a little effort into it, people.