At the end of 2001, a participant was involuntary terminated as part of the plan's partial termination. He became 100% vested.

He was rehired 7 months later. Are his 2002 and 2003 employer contributions also 100% vested or does the regular vesting schedule apply to those monies?

They don't have to be, so they probably are not, but look at how the plan is worded. The 100% vesting applies to money in the plan at that time, later earnings on those earlier amounts and later contributions don't have to be fully vested if the document is written correctly.