It's a Wonderful Kingdom

The Choice Phase alternates Offering and Selection turns for 16 successive turns; the first player for the round (indicated by the round tracker) makes the first Offering and will be the last to Select that round (so Offer and Select alternate until hands are empty). (page 3)

Yes — you may spend 1 or 2 Trap tokens when adding cards to the Offering areas to place those cards face-down; nobody may look at face-down cards in Offering areas and if selected they go face-down into the Selection area and are only revealed in the Planning phase. (page 3)

When you recycle during the Planning phase you immediately collect the Recycling bonus and place those Resources either onto your Alchemy area or onto cards under construction, and if placing that resource completes another card its construction resolves immediately (and that completed card can produce later in the same round). (page 4)

No — only cards in your Duchy (completed) count for production; cards under construction are ignored, though if you complete a card during a Production step it is added to your Duchy and may produce in subsequent Production steps that round. (pages 4–5)

Whenever you have five Resource cubes on your Duchy’s Alchemy area you immediately discard them to gain one Krystallium cube; Krystallium can be kept indefinitely and may be used at any time as any Resource cube or to fill a space that specifically requires Krystallium (but it cannot be used as a Soldier). (page 6)

You may discard a card under construction at any time and you receive its Recycling bonus placed into your Alchemy area, but any Resource cubes and Soldier tokens on the discarded card are lost and return to the supply. (page 6)