Quickcast before a creature's action phase

[exid]

I didn't find the answer in the FAQ... hope I didn't miss it.
it's about the quickcast action used immediately before any creature I controle takes its action phase:

must I tell wich creature I will activate before the quickcast, or can I choose it after the quickcast is resolved?
(extreme situation: can I decide to pass after having resolved the quickcast?)

[Wildhorn]

You do not need to declare which one.

You can't pass after QC. You have to activate something.

[lukard]

Rule book (pg8):
You can use your quickcast action at three times during the Action Stage:
• During the First Quickcast Phase
• Immediately before or after any creature you control takes its Action Phase
• During the Final Quickcast Phase

When it is your turn to take an Action Phase, you must activate one of your active creatures. However, if your opponent has more active creatures in the arena than you have, you may choose to pass when it is your turn to take an Action Phase.

Rule book (pg9):
When you choose a creature to take an Action Phase, you activate it. You must flip over the creature’s action marker to the inactive side, and you must discard any guard marker (if it has one). Then your creature may take its actions for the round (see “What Can A Creature Do” on page 11).

Note: As soon as you activate a creature and flip its action marker, your opponent can reveal any hidden enchantments
(see “Revealing Enchantments” on page 18). You must give your opponent a chance to reveal his enchantments before
you decide which action you want to take with your creature.

Remember that before you activate a creature (including your Mage), or immediately after you have completed its Action Phase, you can use your quickcast action (if your quickcast marker is active).

----------------------------
In my understanding  we can break it down as follows:
#1. Choose to take actions or pass
#2. Opportunity to use your Quickcast Action
#3. Activate a creature (flip the action marker)
#4. Ask opponents if they want to reveal enchantments (you can also reveal your own enchantments)
#5. Carry on your action phase

Therefore, you can choose the creature after resolving your quickcast, but you cannot pass if you used your quickcast.

[Zuberi]

In my understanding  we can break it down as follows:
#1. Choose to take actions or pass
#2. Opportunity to use your Quickcast Action
#3. Activate a creature (flip the action marker)
#4. Ask opponents if they want to reveal enchantments (you can also reveal your own enchantments)
#5. Carry on your action phase

That is a pretty decent way to think about things, except that it could be a little misleading regarding Enchantments. I might change it to:
1. Decide whether or not to pass.
2. Opportunity to use before action effects (such as Quickcast and Conjurations).
3. Activate a creature.
4. Option to move the creature.
5. Option to take action with the creature but can not take a Full Action unless they did not move.
6. Opportunity to use after action effects (such as Quickcast and Conjurations).

Enchantments may be revealed between any of these steps, and between any steps that may be involved during one of these steps (such as the Cast Spell steps or the Combat steps). You must give your opponent the opportunity to reveal before proceeding on to the next step.

[exid]

thanks!

(it's the way we play it but I wasn't sure)

[Shad0w]

Luk and Zuberi thank you