Apple has absolutely nothing to worry about. When they bought the parent company, the contract would have specified that the rights to the name were given to apple. If the company did not own the rights, then the liability shifts from Apple on to the parent company that sold the rights.
Worst case scenario is that Apple gets told to stop producing iPad's for sale in China and must either buy the name, or change the name. And no, they can't just claim they want $xxx for the name, it goes off of the value of their "I-Pad" products, but that doesn't mean it will be $55,000 they bought it from the parent company at...
Eh? Apple didn't buy any company, so not sure what you mean there. I think you mean they bought the Ipad trademark, but unless you've seen that contract you have no clue as to what rights were/were not included in it.
Anyway, you're basing your assumptions on law as you know it, and unless there is a Chinese trademark expert on these forums everyone here is making wild guesses.