All of these are signs of ungrounded energy practice, except the last. These are energy discharges, ungrounded, upsetting the energetic system. A method that does not properly ground the energy can IMO never be a Water method.
IMO the difference between Fire and Water methods is not the direction of the energetic current. The direction of the current is just a safety measure. Anytime you overwork your energetic system it is not a Water method, though. The Water aspect of gentleness, dissolving is what makes a Water method what it is. Respecting your limits, learning them, and allowing you to stay relaxed. You cannot properly relax something that you work to 100% or beyond (i.e. overwork beyond its innate capacity).
Spontaneous Qigong is its very own thing, it is not necessarily Water either. Nothing in the Water method prevents you from directing energy. If you do it like Bruce Frantzis teaches it, you actually direct the energy downward as a safety measure against side effects like the ones above.
I think the above discernments are too strongly fixated on alchemical aspects, but while the downward current has a cooling effect and can help stabilise your energetic system, this alone does not prevent forcing, strain, overworking, going beyond the limit or burn-out systems. It does however help in grounding. A method is Water if it focuses on uncovering of what is there (removing blockages of physical/etheric, emotional, mental nature) instead of focusing on creating power by activating power by visualisations, forceful energy leading, opening of special channels and so on.
Strong grounding is an important component in a method aiming for insight, because only when you ground agitated energies you can see subtler energies.
I find it irrelevant whether you sit for 20 minutes after such a practice or not - at least to whether it is Fire or Water. First you upset the energetic system, and then you try to sit? It's like the remedy for the damage done by the method itself. I'd guess if you'd leave out that component the method would leave you agitated and over longer periods a nervous wreck.
BTW, I did not practice nor know Kunlun in detail, I just was citing the promised effects the practice has - sweating, speaking in tongues, crying, hysterical laughter and so on. Anyone welcoming such effects in practice is already on the Fire path, no mistake. These effects always happen as side effects of improper grounding and overworking, and are only signs of progress for those who do not care what they actually do to their body, mind and soul in the search of power.