If indeed there is a connection between Loki and Laguz (which I believe there is), it probably has to do with three of Loki's aspects: Loki's ability to shape shift, Loki's destructive aspects, and Loki's ability to lie and obscure the truth/reality.
First off, Loki is well known as the shape shifter. This is also a well known property of water: it is the only substance found in nature that is found in all three states of matter (solid, gas, and liquid). Water also can take any shape, usually the shape of that which contains it. It can also (in the form of ice) be carved or frozen into a variety of useful shapes.
Second, water can be extremely destructive, especially in the form of a tsunami, a hurricane, or as a solvent. Brackish water can be a poison, able to make a healthy body ill. Water is also home and breeding ground for all kinds of nasty creatures, including malaria carrying mosquitos, snakes, alligators, sharks, etc.
Third, Laguz is stagnant, murky water. This sort of water obscures. It acts as a reflective surface, but reflects back a darkened picture, not an accurate resemblance. Should the surface of the water be disturbed, so will the image on it be warped and distorted.
There is a fourth connection between Loki and Laguz... Loki bares Fenrir, Hel, the Midgard Serpent, and Odin's horse, Sleipnir. As he gave birth, so does water. If we are to believe Darwin, all life came from the ocean. Our word 'Mother' comes from an indo-european root word, 'Ma', meaning 'Ocean', 'Mother', and 'Goddess', and is the same 'Ma' that refers to the dark indian mother goddess, Kali. Loki, being kin to the Jotun might be concidered the son of water.