It depends on the airline. Most allow MP3 players (and all American carriers do). You won't be able to use the player (or any other electronics) until after the plane has climbed above 10,000 feet (about 3,000 meters).

Your airline will have a webpage that describes what you can and cannot take. For the most part, the limitation is primarily on anything explosive or flammable.

You won't have any problem with tea. My wife brings home tea from China all the time. I doubt that cake will be problem. Goat cheese, on the other hand, may be.

From the U.S. Customs website:

Food Products
Bakery items and all cured cheeses are admissible. The USDA's Animal and Plant Health Inspection Service (APHIS) publishes a pamphlet called Travelers Tips, which offers detailed information on bringing food, plant, and animal products into this country. Imported foods are also subject to requirements of the Food and Drug Administration.

Fruits, Vegetables, Plants
Many fruits, vegetables, plants, cuttings, seeds, unprocessed plant products, and certain endangered plant species are either prohibited from entering the country or require an import permit. Endangered or threatened species of plants and plant products, if not prohibited from importation, will require an export permit from the country of origin. Every single plant, plant product, fruit, or vegetable must be declared to the CBP officer and must be presented for inspection no matter how free of pests it appears to be. Most canned or processed items are admissible.

Applications for import permits or requests for information should be addressed to: Permit Unit, USDA-APHIS-PPQ, 4700 River Rd., Unit 136, Riverdale, MD 20737-1236, USA.

Meats, Livestock, Poultry
Meats, livestock, poultry and their by-products (e.g., sausage, pâté) are either prohibited or restricted from entering the United States, depending upon the animal disease condition in the country of origin. Fresh meat is generally prohibited from most countries. Canned meat is permitted if the inspector can determine that it is commercially canned, cooked in the container, hermetically sealed, and can be kept without refrigeration. Other canned, cured, or dried meat is severely restricted.

You should contact the USDA’s Import-Export Products Staff, APHIS-VS, 4700 River Rd., Unit 40, Riverdale, MD 20737-1231, USA, for detailed requirements.

Enjoy your trip!