Yes, the Water punches in the Five Element Fist are rising backfists (like waves, hence the name) that target the underside of the jaw.
The canonical order, at least in the Wong Fei Hung system, is always in this order:
Dragon (Earth), Snake (Water), Tiger (Fire), Leopard (Metal), Wood (Crane).
Each of these has its own aspect in Cantonese (Mandarin in parenthesis). These are sometimes called the Ng Jing (5 essences). The ones bolded are the "internal" animals because they draw on the Neijia school methods (Tai Chi, Xing Yi, Bagua, etc). Many people who are only familiar with the northern, or narrower southern arts are unaware that the modern Hung Ga lineage incorporated all of that internal stuff long ago (but good luck getting a Tai Chi teacher to understand this).
Dragon is sun (shen), spirit. The driving force
Snake is hei (qi), energy. Internal energy flow
Tiger is gwot (gu), bone. Structural frame
Leopard is lek (li), strength. Horsepower
Crane is jing (jin), essence. Your inner battery
This is (right to left), Water, Water, Earth, Wood. The two on the right are rising backfists, the 3rd (from the right) strike flows into a falling hammer fist (Earth), and the last is Wood (squeezing) fist or Metal (Separating) depending on how it's done.
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Fire:
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Wood:
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