Bonjour & Hello!
Do what you love for someone you love. =)
I really appreciate you posting your observations! Setting it at two was our attempt to make it as quickly achievable as some of the other achievements. Because you can get 3X more of the other resources than quests (and quests actually can't stack) this was intended to allow players to complete this as quickly as an apple delivery or pie fight for example.
With that said, it's absolutely fine to scale it up to make extend the game. (as long as you feel it doesn't put this achievement out of reach relative to other achievements) I'm currently working on a matrix to help players adjust the game setup for different ages and desired game length. (some adults felt that 30-45 mins was too short)
Players gunning for certain victory conditions may choose to bypass going for quests altogether. But if you're intending to max out both Friendship and Pies then the right quests will give you a huge advantage.
I've played this a couple of times now, and it seems to me that the star for completing 2 quests is just a little bit too easy. Most players seem to get that almost by accident in our games.
Are we perhaps playing wrongly, or do others think it should be 3, or even 4, quests?