In all versions of Catan, is it permissible to place the Robber on the desert or an unoccupied tile?
Yes, thanks to the rule change in the 4th Edition of the basic game. Here is a cut and paste from Mayfair.
Q: Are there any rules changes?
A: "No" is the short answer. We have cleaned some text up in the rules for Cities & Knights, and we have changed a rule for The Settlers of Catan to match the new international standard. The changed rule affects the robber: "The robber may now return to the desert even after moving out. Thus, a player may choose to move the robber back to the desert rather than to an opponent's hex, if the player chooses to do so."
If placed on the desert when an opponent has a settlement on it, do I still steal a resource?
You may still steal a resource.
In Basic Settlers, there is a specific order of play on one's turn: roll, resolve the roll, trading phase, building phase. In Cities & Knights, the trading and building is merged into a more freeform phase, yes? One could build on a port and use it on the same turn in Cities & Knights, but not in the Basic Settlers, right?
Correct. The FAQ at Mayfair says the rules were streamlined in some of the expansions to make the games play faster.
In Basic Settlers, development cards may be played at any time during one's turn, even before the roll, but only one may be played (excepting victory points of which many may be played) so long as they were purchased on your last turn. Is this correct?
Correct. Slight correction though, VP Development Cards can be played as soon as you get them, and you can play as many VP Development Cards in a turn even if you've already played a non-VP Development Card.
In Cities & Knights, progress cards may be played at any time during one's turn after the roll (excepting the Alchemist which must be played instead of rolling), and any number may be played regardless of when you received them. Is this correct?
Correct.
In Cities & Knights, what happens if the barbarians cause a player to lose a city when they already have all of their settlements on the board? Are they left with nothing?
From the rule book "if you lose a City to the Barbarians, and all five of your Settlements are already on the board, you must turn your City on it's side: this City is treated in all ways as a Settlement (it is worth only 1 victory point, it produces only 1 resource, etc). If you would like to build a City later, you must first rebuild the "reduced" City. You must pay the normal costs (3 Ore and 2 Grain), then you can turn your City right side up again. You may not upgrade the reduced City to a Metropolis. You must first repair the damage done.
If the above situation occurs and leaves a road with no settlement... that would bring up some other questions. Does the road stay if it's by itself? Does the road stay if it has a knight on it? Can the player build off of this road? If there's a knight there, does the knight stay put if it's road moves?
Moot.
In Cities & Knights, regarding the "Diplomat" card, is it legal to remove a road that has at it's end a knight, settlement, or city belonging to a different player?
No. You can't remove a road that has a structure at both ends.
In Cities & Knights, does the Progress Card "Merchant Fleet" allow the user to make multiple trades using multiple resource types like the 3:1 port does, or must the user declare a resource type to make trades with, like a short-term "Merchant" card?
The latter. The player who plays the card must choose 1 resource or commodity to trade at 2:1 for the rest of the turn.
When combining Seafarers with Cities & Knights, may a Merchant be played onto a Gold Mine hex to grant the owner a wild 2:1?
I would contact Mayfair directly about this question. You can reach the rules guru at:
rulesguru@mayfairgames.com My gut reaction is that the question is moot because you can't mix C&K and Seafarers. However, I don't own Seafarers, so I can't look up that rule.
Thank you for reading this, I hope to have a reply soon.
No problem!