8th Ed. Doubles help.

[Danger Goat]

Do both armies have to be legal individually? Or could 50% of your army be rares, as long as it fit within the 25% overall limit? Just curious. And that is just an example.

 

[Battlehamster]

I would say go with the high elves since they complement lizards pretty well. Their high initiative combined with your raw fire power should win the day. And their mages plus your mages = win for your magic phase. But that's just me.

On a side note, I just wouldn't take the Skaven partner just on general fluff principle. I like to roleplay my army at least a little bit and I don't see Lizards ever finding common cause with the Ratmen.

 

[zenoren]

You might want to find out how the Magic Phase plays out at that Tournament. The reason I mention this is because it would be nice to know how many dice you are going to get for Winds of Magic.

If both armies have to share the 2d6, then I suggest Lizardmen (magic heavy with a Slann) team up with something that's not as magic heavy. Or the other way around. If you can go with 4 Stegs at 1500 points (1 EOTG, 3 regulars, 1 ancient) then your partner could go heavy magic to help protect you and still use up all those magic dice.

Otherwise, both armies having 2d6 each would make it more beneficial to join forces with High Elves or someone who is also magic heavy... and then you can over power the enemy during the magic phase.

Also, if you bring the muscle (large blocks of saurus) then have your partner bring something complimentary. Either Flankers or lots of shooting: Tomb Kings obviously comes to mind (chariots or tons of cheap archers).