Depends on your view. Half-life and the Half-life 2 games were made made by Valve, as was Portal. A different company (Gearbox) made the half-life expansions you listed, and are not considered canon by some players. Personally, I think they make sense in the HL universe, so use them as backstory. In the end, it's up to you, but the main (ie. definitive) games that make up the plot are:
HL2: Episode 1
HL2: Episode 2
Use the other games as reference (as I said, I do), but you may find that any details have not been considered by Valve, as the did not make OpFor, BS or Decay.