yes
White? Do you mean egg whites for a meringue icing? If so, you can't substitute for egg whites unless you have purchased powdered egg whites. Do you mean white as a color and flavor? Any color/flavor will do, depending on your taste.
Any raw egg white.
I found the following on an article by Pat Lock. The title 'royal' was given to royal icing after being used on Queen Victoria's wedding cake in 1840. Francatelli, the Queen's famous French chef, published a book in l864 in which he describes how to ice a wedding cake with a mixture of egg whites, sugar and lemon juice beaten together. He wrote 'use this icing to mask the entire surface of the cake with a coating about a quarter of an inch thick'. But, long before the above date this type of icing was in use. A cook, wrote in 1789, that she spread it over cakes with the aid of a board or a large feather! And then placed it in front of 'a great fire' to dry. So we can see royal icing has been popular for many years. The simple ingredients, egg white and icing sugar create a dazzling icing, making it the perfect choice for wedding cakes. Dried egg whites can be used instead of fresh. Not only does this save having a surplus of egg yolks, but also the icing is whiter than icing made with fresh whites.
sugar and egg whites are the common ones
Royal icing and butter icing are completely different products. Royal icing is made with beaten egg whites (often as dry egg white powder) which break down when in contact with any fat or oil. Butter icing has a very high fat content, so the two types of icing are not compatible. If for some reason no sugar is available to make butter icing, it might be possible to reduce completely dry royal icing to a powder in a blender or food processor, then use that in place of powdered sugar for the butter icing. But that would be a very odd way of getting sugar by way of reverse engineering.
Cookie decorating icing is most often Royal Icing. Here are two simple recipes for Royal Icing from my site:Royal Icing with Meringue4 cups confectioners' powdered sugar, sifted3 tablespoons meringue powder1/2 teaspoon extract (vanilla, lemon or almond)1/2 - 3/4 cup warm waterRoyal Icing with Egg Whites2 large egg whites - to be safe, use a ¼ cup of store bought egg white instead of cracking an egg2 teaspoons lemon juice3 cups, confectioners' powdered sugar, siftedBeat all the ingredients a few seconds till all is moist then beat for about 10 minutes till completely smooth. Add sugar to thicken for piping borders and water to thin for filling interiors.
Yes. Many homemade cakes use whipped egg whites for the icing which is raw.
Meringue is egg whites and sugar. There is no fat in it. In fact if you add any fat, it will make it very difficult if not impossible to get your egg whites to become stiff.
It can. But other ingredients (like sugar and egg whites) can also make icing hard. It really just depends on the mix and specific ingredients in that type of icing.
egg yoke
yes
The 3 classic types of meringue are: French-Room temperature egg whites and sugar are whipped until it forms a peak. Italian-Room temperature egg whites are whipped until froth and peaks are just starting to form. Then hot sugar syrup is slowly drizzled into the egg whites while whipping until stiff peaks form. Swiss- egg whites and sugar are whipped over a double boiler until peaks form.