In Germany it's fairly common to call McDonalds "Mäckes", which sounds very similar to "maccas" when spoken. This is an unofficial designation with a slightly negative touch as well, as it's often preferred to the actual name when referring to McDonalds specifically as a provider of mostly unhealthy food.
I don't know, for me Meckes is neutral. The ones with more negative connotations are probably 'Zum Goldenen Adler' (due to the sarcastic undertone) und 'Amerikanische Delikatessen' (due to the perceived oxymoron)
Interesting, I don't know any of your synonyms from my personal experience. The especially negatively connotated variant I know is 'McDoof' (basically 'McDumb' when translated to English).
