A quick Google web search reveals this post for the Easter Festival (yes, it's the same author although a different name). The full rules for both expansions can be found in the downloads sections of Carcassonne Central (you'll need to register, but it's free to do so).
Easter Festival - Rules
Easter Festival - Tiles
City Gates Rules - English translation
English language translations for the base game as well as two expansions are available at BoardGameGeek. Here is a link.
1 Wheat Field
2 Livestock Farm
4 Convenience Store
6 TV Station
6 Business Complex
7 Cheese Factory
8 Furniture ...
The table is at the bottom of page 2. When brewing, add the cost of your gem(s) to the dice roll. On a 3 or less, the brewing fails and you lose the ingredients. On a 4 or 5, nothing happens but you can attempt to brew again on your next turn. Finally, on a 6+, the potion is ...
You keep both. There is no limit, according to the FAQ:
Q. Can an investigator have multiple copies of the same Unique
A. Yes. There is no limit to the number of Unique Assets an
investigator can have.
Good rule of thumb: when looking for a reference for a board or card game, always check BoardGameGeek. Here's the most popular Citadels reference available there:
And you can find a ton more in the Files section of the Citadels detail page.
(I believe you have to sign up for an ...