R' Meir says: We may examine negaim for the first time in order to render a lenient verdict, but not to render a stringent one.  The Sages say: [We may] not [examine a nega whether] for a lenient or for a stringent verdict.  R' Meir also said: A person may gather his father's and mother's bones [for burial], as it is a [source of] joy for him.  R' Yose says: It is [a source of] mourning for him.  A person may not inspire [lamentations] for his dead [relative], nor eulogize him during the thirty days preceding a festival.

We may not hew burial niches nor [build] tombs during [Chol] HaMoed; but we may adapt burial niches during [Chol] HaMoed; dig wash ponds during [Chol] HaMoed; and [construct] a coffin in the courtyard with the deceased.  R' Yehudah prohibits [the latter], unless the boards are at hand.