I'm kind of new to Mileage Plan, trying to figure out a couple things.

Firstly, are you allowed to mix and match as many partners as you want for an award?
From looking at the award chart its kind of confusing, each partner has their own required mileage...

Secondly, can I fly BA, North America-Australia using Mileage Plan? That would be the ultimate in value for miles...

Thanks for any tips.