Great choices and would love to see some of these fights as well. I am a huge U-Foes fanboy and would like to see them battle the Red Hulk. The fight would be epic but I believe Rulk would win hands down with his military experience giving him a huge advantage strategy wise plus the ability to absorb various energy could nullify X-Ray out of the fight.
In regards to the Cyclops vs Havok fight, aren't the brothers immune to each others powers? They could blast each all they want with no physical damage to each other so it would just come down to hand to hand combat.