Apple's two-step verification: Multiple Apple IDs and mac.com Apple IDs?

I like the idea of "two-step verification" for my Apple credentials (aka two factor authentication).

Problem is, I have no faith in Apple's ability to get this right, especially given their many years of unresolved Apple ID problems [1]. In particular I wonder about two things:

• Can I do two-step verification for my core Apple ID that's tied to all of my App Store and iTunes purchases? That is a mac.com address, and when I tried setting one I wasn't given that option. I think the answer is no -- I'd have to change the email address first. But I know I can't change it to one of my 3 other Apple IDs.
• Can I do two-step verification from an iOS device for an Apple ID that's not the same as the Apple ID tied to the authenticating device? (iOS: iTunes and App Stores)

Until I get answers to those questions, I'm afraid enabling two-step verification will lock me out of my core Apple ID services

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[1] Examples below. Their Apple ID failures are one example of why I think Apple's mind-boggling successes of the late 00s may have also broken the company. There are so many things small and large that Apple can't seem to manage. I'm hoping Cook is doing recovery work.

• Apple's identity and account system is screwed up. Again. 2008
• Apple is again messing with Apple IDs – pay attention! 6/2009
• Apple's messed up Apple ID system: what are they smoking?! 7/2008
• Apple ID Hell: Apple's identity mismanagement and an insanely obscure ID bug with MobileMe send as email 5/2012
• My Apple purchase records jumped from true AppleID to one I've never used. This is what I think happened. 6/2012