Well then we should cover the one technique that you haven't included. Seed Steeping.
Simply it is taking 1ml of a well steeped juice and making a batch with it in the bottle. Cap and shake.
I have one recipe that takes at least 2 weeks of steeping to taste great, at least 1 week to taste good, and tastes like nasty crap when first mixed. (I only have one recipe that tastes like nasty crap when freshly mixed and this is the one.) It has been part of my daily rotation for a few months, but I sometimes forget to make a batch far enough ahead, so when I read about seed steeping, I thought it was worth a shot. Did the seed steep (the steep part of the name makes it kinda' confusing as there is no real waiting time) and that recipe was good right off the bat.
Since this is the only recipe in my current rotation that needs steeping, it is the only one I have tried this on. When I do go and mix up some of those recipes that benefit from steeping, I'm going to try it again to see if shaves a week off of everything.
This has to have something to do with flavoring interactions as there is not enough time for entropy to occur.
And that is the reason that observation and trying new things is so dang important. We are dealing with full diffusion, flavoring interaction, flavoring and nicotine interaction, flavoring and PG/VG interaction. It seems reasonable that we can speed all these up with heat, but heat also can have an adverse impact on nicotine and flavoring. It seems reasonable that we can speed some of them up with agitation. It doesn't seem reasonable that speed steeping would have that much of an impact, but it works, so there is something else going on that I haven't been able to qualify.
And all this is ignoring what happens when we breathe juice...