When can I check random '?' port (Seafarer, Wonders of Catan scenario)

Sorry for so many questions :)

When we play random ports with original or original + C&K, we usually shuffle and placing them on their back and open all after initial map setup preparation is over (=before game begins.)

But for Seafarer, I don't know about this, because we now have new fog tile mechanism. For example, for Fog Islands scenario, I know I can only open random '?' tile when I place the ship to the intersection of the fog tile.

Then... what should I need to do for random '?' ports for Wonders of Catan scenario?

a) Can I open them all after initial random placement?

b) Or can I open after I connect a road or ship to any random '?' ports?

c) Or can I open after I build a settlement to the intersection for any random '?' ports?