I haven't tried blending the whole skin into the drink. I suspect it might make the whole thing a bit soup-like, but by all means give it a go and tell us the results, anything to save effort is worth a try in my book.

I prefer it without the Epsom Salts myself, but taste is always very subjective, and many people like the tang.

Sugar quantities are adjustable to taste and vary with the bitterness/ripeness of your lemons anyway, but I wouldn't recommend omitting it entirely.

Incidentally, the more frugal drinker takes the strained-out skins and makes a further batch (about half the size of the first) but it won't taste as good.