Wasn't it Bruno who mentioned the no-content in Mark's cha-cha rather than Len? And he was right: when Mark wasn't doing cartwheels, he was standing there swaying his hips while Lacey danced around him. Don't think that can be blamed on Lacey's illness--this was a dance they'd prepared before last week's elimination.
As to manipulation as to who gets in the bottom three: it's in the show's best interests to promote the more popular contestants, not the low vote-getters. Keeping around someone that the viewers don't care about is detrimental to the ratings. That said, I won't be the slightest bit surprised to hear that ABC has some development deal with the Osmonds or that Mya has been cast in a role in an ABC drama or sitcom. Donny could show up and do the hokey-pokey and not get scored lower than 8s.