A lot of dairy products become watery or start to separate if they've been frozen or defrosted: pastries with cream fillings, cream cheese, sour cream.
The USDA says does not recommend that eggs or canned foods be stored frozen. Eggshells can crack easily, and even if the shells remain intact, the consistency of egg yolks makes them difficult to use for anything other than hard-boiling. Canned foods that are frozen accidentally could pose health risks, so the USDA recommends inspecting to see if the can has rusted or burst. If the can is swollen, thaw it but check to make sure it doesn't look or smell off before eating.
The FDA also has a useful chart (pdf) on which foods don't freeze well and how long you can freeze other foods. (Note: when there is a recommended limit on how long a food should be frozen, it indicates when the quality of the food will decrease - NOT when it will "expire". You could theoretically freeze most foods indefinitely.)
The only other thing I would avoid freezing is any sort of raw green (lettuce, spinach, etc.). Greens wilt and turn brown when you freeze them. (If they're cooked, they should be fine to freeze and thaw.)
EDIT: Apparently, some spices become bitter when frozen, including pepper, cloves, garlic, green pepper, imitation vanilla, and onions, paprika and celery taste different.
I'd never heard of ESL until your question, so I had to look that up. A local company did a lot of work developing UHT milk; I remember samples when they were first starting up production, and they were trying to find flavors additives which would mask the flavor change from the UHT processing. Since then a lot of companies have adopted the processing methods for other products, or just adopted the packaging. So, before I relied on any random box-packed product to be shelf stable, I'd check into how it was produced.
Proper UHT milk doesn't go bad until it's opened. It's sterile, and in a pretty sturdy container. Once opened, bacteria will get back into the container, and the milk will go bad as normal. When the local company started production of UHT milk, they were putting 2 year code dates on packages, and that was just the longest date the government would allow; I've had boxes 3-4 years old, which were fine.
Best Answer
It should be fine. These sorts of foods are commonly sold frozen in the USA and other countries and are easily reheatable in an oven or fryer. They should keep for some time sealed in a plastic container or bag when frozen
Freeze by placing in a single well-spaced layer on a tray, once frozen transfer to a more convenient container. To reheat/cook, heat fryer to correct temperature and fry for approx 5 min. An oven will take longer to cook.