By the way, what does SC stand for?
@FranC is correct; SC is Super Concentrates (the brand... not the generic super concentrates tag like WF-SC, or RF-SC).
Shake and vape or steep? Do flavors really mingle so quickly that shake and vape truly “works”?
For my wonky taste buds, I find that it will vary mix to mix, and has a lot to do with the ingredients used (sometimes even in what combinations).
My usual SOP, when I am mixing a new-to-me recipe or using ingredients I am unfamiliar with, is to do a little test-taste vaping as I let the mixture mature. I generally won't fill the tank... 0.25-0.5mL is usually plenty to get an idea of how the mixture is developing. When it tastes good to me, I deem it ready.
I am only familiar with one of the three you intend to mix: Manner. Manner, per the author's notes, and my own mixing agrees, is 24 hours. I don't mix large batches of this one as the INW Lemon starts fading out after 2 weeks. I have yet to experiment with subbing different lemons, or using lemon combinations, to see if I can stretch longevity.
Do the heat steep methods work well or is waiting the best method?
I personally am not a fan of heat. Heat can accelerate flavor loss ("fading") in some concentrates (lemon concentrates seem to be especially susceptible). Concentrates that have more aromatic notes tend to be more susceptible: berries, citrus, fruits in general, and florals, are just some examples. Concentrates with little aromatic presence fair better: custards, creams, and some tobaccos, seem to tolerate heat treatment without much flavor loss.
If you are itching to experiment with heat (and there are DIYers that do like to use it), I suggest mixing your recipe, and then divide it into two smaller bottles. Heat treat one, and let the other age naturally. That way, you can compare for yourself, and see if it is something you want to pursue.
