Who would win in the following scenarios:
1. Personal fights using weapons, technology, etc
2. Using resources available to each
Combat goes to Mandarin and Red Skull, heck just Mandarin alone. He's a complete monster, superhumanly skilled, iron-willed, immensely powerful.
Prep is extremely close, but I'd give a slight edge to Vandal and Ra's. Mandarin's strength is also his weakness to a degree: he likes to fight fair, to prove what a warrior he is. He tends to prep to conquer the world, but doesn't prep much to beat individuals. Looks at his last fight with Iron Man, lots of missiles to destroy the world, but no traps or gizmos to fight Iron Man himself. Iron Man he fought fair. Or his fight with the Avengers back in the day. He did this big scheme to conquer the world, but when it came time to fight the Avengers themselves, he fought fair, even passing up a chance to shoot down their ship. He feels a big need to fight honorably, at least when he deems an enemy worthy.
Vandal and Ra's feel zero need to fight honorably. They will cheat shamelessly, and that will get them the win here.