One thing that's helpful is that with Krayt on the field, the Sith Emperors can go for mutual kills. If two sides get stabbed in the heart, and one side has someone that can heal lightsaber wounds... it's a big tactical advantage.
Scenario I: They stop at 3, but they take 2 with significant difficulty, to the point where in scenario 3 the Jedi would take them to the curb.
Scenario II: Still stop at 3.
Scenario I: They take the first one in a pretty awesome battle. They lose at 2 in a good fight, and maybe they get to 3.
Scenario II: They do pretty well in the first 3, but every time it's a very good battle. They get curb-stomped at 4, however. LOTF Luke could give the trio a decent fight on his own. With Starkiller and Satele at his side, this is overkill.