Soy milk works great in pancakes. My basic recipe for pancakes is about a cup of flour, about a cup of soy milk, a tablespoon or two of sugar and veg oil, and a few teaspoons of baking powder. Works great, makes nice, fluffy pancakes. (I know, not a "recipe" so much as list of ingredients with approximate proportions, but that's how I tend to cook, experimenting and learning from experience as I go...)
Edit: I don't know about scotch pancakes; I've never made them, but upon looking up a couple recipes, I don't see why it wouldn't... Soy milk behaves much like milk in these kinds of recipes, the only difference being that soya adds a bit of binding that dairy milk doesn't (and perhaps a smidge of a taste difference?)
Edit2: Haha, ok, so my "pancakes" are much more like your "scotch pancakes" -- there is such a wide spectrum of "pancakes", from crepe-y types to big, fluffy types... So then, yes, I'd say soya'd certainly work fine for scotch pancakes; for your "pancakes", I still suspect it'd be alright. With crepes mainly you just need liquid (hence the mixing with water in your posted recipe) -- the milk is mainly for some added flavour; I'd conjure that soya would work just fine.
If you've found a very old recipe that calls for scalding for food safety reasons, then yes, it is probably unnecessary. However, there are places where it is called for.
In particular, when making Béchamel (which is made by combining milk and roux), it is important to scald or at least warm the milk, otherwise you can and most likely will end up with lumps. The reason to actually scald as oppose to simply warming the milk tends to be one of cooking time; the hotter the milk is, the less time you have to spend whisking.
In general, any recipe that calls for milk and needs to thicken tends to benefit from scalding for the latter reason - it just takes less time to thicken that way.
Best Answer
It is safer and helps increase the shelf life of the milk.
Otherwise the milk will pass through dangerous temperatures and and may be recolonized with air born pathogens. These will grow rapidly during the period the milk is warm, and more slowly once it is refrigerated. While the milk may not become immediately unsafe or unpalatable, its storage lifetime will certainly be reduced.