I disagree with some of your conclusions:
2) is not counterproductive. Magazines are in business to stay in business. Few want the electronic version. Those that do, recognize that it's more useful than print. What AH is doing makes enormous sense...it's not designed for the "Subscriber to Each Issue" crowd, but to those who have an interest in a feature here and there. Consumer Reports has been doing this (successfully) forever.
"Mags prosper as verifiable eyeballs increase due to advertising."....yup, that's what the Distributor will tell you. When you hit the Advertiser up for an increase, he states, "Mags prosper as verifiable eyeballs increase due to Content". One tells you the Advertiser will pay; the other tells you the Subscriber will pay.
Luci's Law: "Mags prosper by providing an honest, value added service by which EVERYONE pays (a little)."
3) is hardly "irrelevant". The (economic) purpose of a magazine is to sell magazines. I'm not looking to be in the E-Zine business....it's not economically viable except under a very different model. I'm willing to provide a value added electronic product; it can be free if it promotes newsstand/subscriber sales. Or it can be on a pay as you go basis. But it's got to make economic sense.
4) is not counterproductive if it's priced correctly. It appeals only to those who are specifically looking for a Back Issue; not to "bargain hunters". And it makes sense if that's the only way you offer Back Issues. This is not a real big revenue source for any magazine.
Your concept for assuring security is workable but, I think, cumbersome. Many people have dynamic IP's....AOL, for instance, might provide a match on only the first trip after as little as a 10 minute hiatus. And the goal is not to make the download more difficult (by adding steps).
I'm not convinced that you'll see S.W.A.T. go electronic in its entirety anytime soon. Back Issues and free mini-SWAT's. That's about as far as I'll commit.