Luv2Shop, I think that's pretty ridiculous. He's "exhausted"? It's Broadway, not regional theatre. If you can't handle the demands of your role, then set a schedule you can handle and make that available to the public. I don't see why that's so hard. Shooting schedules are much more predictable than you'd imagine, he's not getting calls at 12AM on Monday night that he'll be working all day Tuesday. Also, you say in one breath that the role of Evita is too demanding and that's why an alternate is required, and then go on to say that Jeremy must be "exhausted" and thus unable to meet the demands of playing Jack and that's why it's excusable for him to be out. If Jack is such a demanding role that he cannot play it 8 shows a week, then it isn't all that different from Elena's situation.
There is no difference between EVITA and this. If you're going to have an alternate, then the schedule should be publicly available. The ONLY difference is Disney does not bill JJ above the title, which does not entitle one to a refund should he be out. To me, that necessitates the need for a public alternate schedule further because if one does go to see him specifically in a role he was nominated for a Tony for and he is out for whatever reason, there is no obligation for the box office to issue a refund.
"Get mad, then get over it." - Colin Powell