The first stage of Elly's exit strategy from being alive would be to come up with a love interest for her. Thelma Baird had some guy named Ed, Jim had Iris and Elly will need a man in her life (let's call him 'Bob') who finally values her for who she is and what she wants instead of what she can do for him. This would occur about five years after the start date. While the Caines don't care one way or another, Mike would get his bowels in an uproar because Mommy is cheating on Daddy.
Stage Two would take place after another five years and would have a newly married Elly and Bob move into a cozy little nook of their own so as to get out of Liz and Anthony's way. What would happen then is that she'd come in every so often to offer Liz advice about her children that would end up being endless variations of "don't make the same frakking stupid mistake your dad and I did and take it personally. I was a jerk to my folks and their kids will be jerks to them." Also, we'd have minor health scares and Elly talking about how it's okay that certain things (like unwedging Mike's head from his ass) never get done because everyone has unfinished business.
This echo of the arc in which Elly felt all gutted when Thelma Baird passed on would reach its conclusion shortly after Elly's seventh anniversary when Liz was surprised by an actual telephone call. Given the rarity of the situation, her first words to the caller would be "When and what of?" before telling the rest of the clan Elly had died. We'd have Liz wondering why she still felt as if she never did enough, complaining about how unfair it was that Elly never got enough of what she wanted to do in life done and dreading the memorial service because Michael would obviously try to make it all about himself. What she would not know is that Elly had a plan for Mike after she died: public exposure as a fraud and a plagiarist.