Only H-H are untouchable, everyone else is up for grabs.

Only if the price is right. It all depends on their playoff performances. Sadly, if Lin is not traded, it's probably not because he's untouchable for the Rockets, but rather no taker is willing to pay him 15 million next season.

To trade for a third star, you need to put together a package with value and contract (normally bad but expiring contracts) to match. In this CP+JL case, it doesn't mean Parsons is all good and Lin is all bad, just valuation-wise, with their current contracts.