Not to the T. Molasses + lemon in water will definitely be safe, but I would forego cayenne, the purpose of which is to irritate the stomach lining into secreting more stuff. Normally the idea is that the secretion will dislodge anything stuck in the intestines, but a 31d wf will have taken care of that already - while wf the body has all kinds of ways to clean itself: some ppl get diarrhea of vomit or have weird tarry bms, and the lining of the intestines renews itself anyway. The cayenne won't kill you but it will irritate the stomach unnecessarily while not contributing to detox or to weight loss in any meaningful way.

The part I would be worried about, though, is the salt water flush. I think that doing SWF (Salt-Water-Flush) after a prolongued wf fast will be dangerous. First, you are introducing, at once, large amounts of sodium into a body that run low on electrolytes. You will be creating an electrolyte imballance - way in sodium's favor as opposed to potassium, magnesium, etc - and I would be seriously worried for the impact of this on a person's heart and blood pressure. I would be seriously worried about the impact of this on a person's kidneys - during a wf, the kidneys do a lot of work and this will be stressing them additionally. I will be worried about the impact of this on a person's adrenal glands - there are theories that, because salt is a stimulant, high salt consumption is one of the contributing factors to adrenal fatigue.

A SWF (Salt-Water-Flush) is hard on the body, but survivable, during normal times --- after an expended wf, though, when a person's organism is pretty delicate and needs proper rebuilding, I would be really, really, hesitant to use it.

tl;dr: is it safe? yes lemonade, meh-to-no cayenne, hell no SWF.