'Gain Vision Vapor' and 'Gain Spell Fragments' quests should have a choice. I have a chapter 10 city and one that will reach chapter 3 just before the event starts and I decided to not go out of my way to complete these quests.
The smaller city doesn't have that many instants, enchantments or summonings to gain that many spell fragments without using the newly gained rewards just to complete these quests. There is nothing I would craft at this level- not to mention that I started thiis city after the phoenix event so that not even pet food would be required which means there is no way to gain the vision vapor for this city.
My bigger city doesn't have the problem with spell fragments, but the vision vapor quest might still cause a problem. I only craft pet food and if I can't play an event at my own pace, because I have to wait a few days, a week or more for the next pet food to appear in the crafting window, I rather abandon the whole event all together.
If they would re-evaluate their 'Grand' prizes before the event starts, it might be worthwile crafting something to disentchant it with the next ' gain x spell fragments' quest, but at moment I don't consider their 'grand prizes' 'grand' and not investing anything just to complete the quest line/ gaining the 9 artefacts.
Btw, what will be the reward once all artefacts for this building have been gained? Do they chance the artefacts to phoenix artefacts or just take out the artefacts, leaving the library, wishing well, ferris wheel and monument?