Rewards
Dropped in the middle of a complicated web of magically-controlled cardinals, players could get overwhelmed with the number of supernatural agents manipulating the cardinals. Remind them they there were only asked to stop one of the antagonists, and the story is a success if the player characters stopped the supernatural interferer they were initially asked to stop. Stopping more than one is phenomenal. Regardless of whether the player characters succeed or fail, all surviving characters should get 9 experience points for going on the story.
Each magus and companion character also receives Confidence Point rewards. Each surviving character gets two Confidence Points. Stopping the threat he was asked to stop gives the character another. Uncovering a different threat and stopping it grants another Confidence Point, to a maximum of 3 more. Staying impartial and letting the cardinals pick a pope themselves grants a Confidence Point. The maximum Confidence Point award is 7: 2 for surviving, 1 for stopping the threat he was asked to stop, 3 for uncovering and stopping threats that the character was not asked to stop, and 1 for not magically picking a pope.
There are other material rewards. Both Alyates' magic cup and bracelet can be considered spoils of conquest. Vis can be found in both Alyates and Buonacorsus' laboratories. Alyates might have lab texts of his spells and some tractatus on his highest Arts scores.
Depending on how obvious the magi were, they may have formed a relationship with the new pope. There is no telling how this could unfold, positively or negatively, but at the very least a storyguide could develop additional stories based on the pope remembering the strange men and women who saved him. Less honorable player characters may have actually helped pick the new pope; perhaps they insist that he owes them a favor and try to capitalize on it. At the same time this angle can be ignored. If "The Cardinals' Decision" is a one-time adventure, run by a beta storyguide or as a break from your regular saga, the ramifications of interacting with the next pope do not need to be large at all.
Rewards
If the characters succeed in resolving the King's Ransom plot, they gain access to a ready and reasonably safe entrance to the Magic Realm, via the pathway to the Brass Horseman that lies beyond the Marble Palace. They also gain the loyalty and respect of King Kush and Prince Keshan and their army of potent spectral allies.
It is also possible that the characters wind up with one or more genuine Brass Bottles, or otherwise gain the services of powerful jinni or 'afarit. All can provide valuable Insight for Breakthroughs involving spirit mastery or magical servants. The 'afarit can also be allies that add to the magical resources of their covenant.
As for material rewards, the characters are able to take home as much mundane wealth as they can carry. It is freely available and has no value to the magical inhabitants of the city, since the amount of it is virtually infinite.
Finally, as part of the adventure is set within the Magic Realm, characters may accumulate vis instead of experience points while within the Boundary containing the city if you are using the rules in Realms of Power: Magic.

Rewards
Eustace's pirate fleet lacks trustworthy crews, but if it was repurposed it could be the germ of a powerful trading empire. Sark is not really suitable as a trade base, because its ports are too poor, and it lacks many of the resources that shipyards require. Winchelsea is a major port, and the facilities owned by the diabolic merchants, once purified and repurposed, could provide logistical support to the fleet.
Sark is an excellent site for a secluded covenant. The island has few resources, although small amounts of silver and lead lie undiscovered on Little Sark. It is, however, on an almost direct line between Winchelsea and Coutances, two of the busiest ports in the Channel, so the purchase of needed supplies should not prove difficult.
