Kaiba gets stomped in scenario 1. It'd be like Yugi's duel with Marik in the finals, only there isn't a second God to compensate for the loss of the first after Ra God Phoenixes it to death early in the duel, meaning the most Kaiba could do is summon Blue-Eyes with the Fiend Sanctuary tokens for a direct attack, but no Blue Eyes will save him when Ra is brought back for a One Turn Kill. Kaiba even said beating Ra with one God was next to impossible, a probability of 13% even if Marik's stronger monsters were all Crush Card Virus'd out of the deck.
In scenario 2, Kaiba has better odds but needs good draw luck to draw Soul Exchange to sacrifice the Egyptian God Slime to bring forth his Blue-Eyes for a direct attack, and even that's possibly not going to work if Marik stops his attack with Mirror Force or the Spell card he used to stop Jonouchi from directly attacking him and then draws another Monster Reborn caller or Lava Golem to disrupt his combo.
