Just curious, what makes you think Shogun would wreck Mousasi hard? I know it's mmamath but Shogun did get submitted by Sobral, and Mousasi walked through him. There's probably no one at LHW who'd make Mousasi look bad.
It's an old-style tourney so I'll say that it's pretty much Vale Tudo rules, so Shogun can head-stomp and soccer kick people to his heart's content. Shogun with all of his Pride moves plus the UFC's elbows would be pretty much unstoppable, and only Fedor or Anderson Silva would be able to beat him.