I hear that Skin So Soft works on midges, but I've never had the need to fight off midgets.
Re: the sausage debacle. A public service announcement for non-Scots.
I admit that I'm not overly found of Cumberland sausage, but managed to hold myself together when I was served this in Cumbria. In Scotland, if you really don't want Lorne/square sausage for breakfast, the secret is to ask for link sausages.
Re: language difficulties. While the lingua franca of the United Kingdom is indeed Standard English, I would recommend avoiding all areas where one might encounter a different language or dialect.
In Scotland, this means avoiding any areas where Gaelic is spoken. (Mainly the Western Highlands, various islands, but other Gaelic speaking areas are available. If you venture to Canada, under no circumstances should you ever visit Nova Scotia!)
In order to avoid ever encountering the various dialects of Scots, a cognate of English*, I would recommend avoiding all towns and villages. You might be safe in some parts of Edinburgh, but I wouldn't risk being over-confident.
*See histories of Jamie the Saxt/James I for an explanation of how Scots was "lost" as a literary language.