Yes, you can find them on the offical website of Repos Production (rprod.com):
7 Wonders base game
http://rprod.com/index.php?page=download-2 (there you can find the Quick Rules, too)
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
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.
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 ...
Boardgamegeek has a section where you can look at games released within the last 1/3/6 months, as well as unreleased games based on their expected release. It then lets you sort these by number of people with it on their wishlist, which should give you an idea of how popular they are.
Pick up a bag of Chessex Blank d4s. (It's product number CHX29301, ask your Favorite Local Game Store). Grab a Dremel or Power Sander and take off the points. Then sharpie (or carve) the numbers in by hand. That's going to be your cheap route, unless someone decides to kickstart a project like this. Certainly cheaper than buying 3d printed versions.
The most reliable data is usually to troll the various publishers' websites. For a singular point of information, it varies by game type.
Miniatures Games: The Miniatures Page
For Board Games and Card Games: Board Game Geek, especially the Recent Releases page.
Somewhat less reliable: online game retailer websites, such as Boards & Bits, Thoughthammer ...
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 ...
Turns out you can just select a cheaper material on that 3D printing site. So, whilst it's still more expensive than the usual 50c for a die, given that these type of dice don't seem to be as common as I expected it seems like a reasonable solution in my case.