Thanks for putting this spin-off discussion aside 
Ok, 2 things to consider about this:
There are Edge uses that can be performed before any potential Edge-generating Action is declared (and thus, new Edge is generated). In the QSR alone, there is
- 1 Edge for +3 Initiative
- 2 Edge to give more Edge to your Allies (at a loss, but hey...)
- 3-4 Edge for healing Stun or Physical Damage
- 5 Edge for something extra special. That one is a gamble on your GM´s goodwill, but with this price tag, you can expect it to be something worthwhile.
That´s not the full list, more Edge uses might follow in the Core rules and in supplements.
Second: You cannot safely assume that you will generate Edge on the first Action you take or that´s taken against you. Opposition will be less likely to target you first if you are an unvavourable target that will likely get Edge from the Attack (and no, your GM is not supposed to play the opposition out as if they magically know that Player X is already "full of luck" and wouldn´t get more Edge
). And if you go first, the juciest target for Edge gain purposes might often not be the first one you want to take out.
Thank you Fin. That addresses my question. If you can expend edge during lead in, then the problem is workable.
As to your previous point in the last thread Fin yes the edge limit change reads like fairly classic mistake, but who knows. You never really know what the gamer base will do or like with total certainty.
On your second point, we are looking at Potential/Opportunity costs, you build to your satisfaction, you employ tactics to the level is appropriate for your character. But in the end you get edge or you don't. The build works or it doesn't. If your build a strategy including edge or not, and have taken the steps will hopeful lead to the build being effective, then follow the plan, and it doesn't work then you make a new plan and trying something else. Just as we have always built characters.