Sorry, there's been absolutely no proof whatsoever that Jack and Harold ever met each other before the Titanic. That is certainly something I would have loved to have found out as true, but alas, there's nothing to substantiate it thus far. (Not even that oft misidentified "Adriatic" photo).
As for Jack being found in the collapsible, this originally comes from a comment Harold made in his NY Times interview. He had said that it was Phillips he saw, but considering his state of mind at the time, I would attribute that to more of wishful thinking than any intention to mislead.
And I had to look at that website again...oh, dear, that's not the best site for accurate information about Harold, I'm afraid. The young woman who put that site up caused rather a stir some years back by claiming a love triangle between Harold, his fiancee at the time, and the woman he eventually married. Which could almost sound plausible, except for the fact that his accquaintance with the two women occurred at two totally different times, not connected with each other.
Plus, there was the matter of a fabricated diary from Cyril Evans, but that's another matter entirely...