Denise and Malcolm both landed in internally divided dysfunctional TC-untested tribes after the Matsing dissolve. The divides in Tandang turned out to be unimportant (until the merge) as they kept winning immunity, but at Kalabaw they were suddenly forced to go to TCs and Denise had to make her own way to survive. She learned to play the political game while Kalabaw sacrificed two of their own (and lost one to a medical evacuation).

Anyway, if the three remaining Tandang share reward this time, I can't see why that would be unless somehow Abi wins the reward and shares it with Lisa and Michael. No one else has any reason to leave Denise and/or Malcolm out and share with her, but it totally goes along with her campaign to stay in the game. Neither Lisa and Michael would really want to leave Denise and Malcolm together alone to plot.

Denise then must win II. Malcolm doesn't need it, and they all know he doesn't need it since all know he has his HII, so why would he go all out. He would try to win only to prevent someone else from winning, but not Denise.