Cyclades

No — the rules forbid making an offering you cannot pay; you must be able to pay the full offered amount (p.3). Priests reduce the offering by 1 GP each but you must still pay at least 1 GP for an offering (see Priests, p.4).

Yes — if you are outbid you must take your marker back and immediately bid on a different God; any chain of outbids must be resolved before the next player places an offering (p.3).

No — a Creature’s power must be used immediately when bought and then the card is placed in the discard pile; new Creature cards are only placed on the track at the beginning of each cycle (pp.3–2).

Apollo requires no offering (you may place your offering marker there without spending), and grants 1 GP if you own more than one isle or 4 GP if you own a single isle; the first player to choose Apollo that round also takes a prosperity marker — Apollo offers no other actions (pp.3,6).

Each combatant rolls one die and adds the number of Troops/Fleets they have; defenders add +1 per Fortress (island) and +1 per Port (adjacent sea spaces), the lowest result loses one unit (ties cause both to lose one), and assaults repeat until one side remains (p.5).

You create a Metropolis by either owning the four different buildings (Port, Fortress, Temple, University) anywhere — you immediately discard them to place a Metropolis on an empty space (destroy buildings if no space) — or by discarding four Philosophers; you can also gain one by conquering an isle that already has a Metropolis (pp.4,6).