Misfortune: Anytime the creature makes an ability check, attack roll, saving throw, or skill check, it must roll twice and take the worse result.
Protective luck: Whenever that creature is targeted by an effect that requires an attack roll, including weapon attacks, the attacker must roll twice and take the worse result.
These look to me as if when they both apply they're the same effect. There's nothing to suggest they stack IMO, or how they'd stack if they did.
bonus of same type (except specific like dodge) do not stack.
spell effects from same spells (two hastes from2 different casters) don't stack.
same effect from different spell should stack unless stated it doesn't (hence all the haste like spells keep mentioning if they stack with haste itself or not. same for keen)
here you got a very lucky fellow (wind keep blowing arrows away from him, he keep bending to pick up coins when an attack is set for his head) being targeted by a very unlucky mob (wind keep shifting his hair in his eyes, he keep on slipping on puddles of water when charging).
i for one would make him roll twice for his unlucky attack and before rolling each one roll that unlucky roll twice(for his lucky enemy ability) and keep the lowest of that roll as the one to compare for the top two unlucky rolls (lowest of 4 rolls).
50% chance the wind will be a problem for him. 50% chance the guy will bend to pick a coin just in the right moment. that is 25% that his attack won't face wind and bending problems