If ratings are purely personal then yes a 1* could get a 7 for tying his boots, 8 if its a very neat bow. The 7* player would need to beat 10 players, finish with a bicycle kick, all the while correctly explaining string theory and whistling Dixie.
I don't think so. Its probably more like +marks for good things and -marks for bad things / the number of people using the Nordeus toilets at lunchtime x the number of times the Nordeus dog licks his nuts + any random number that gives a result between 0 and 10.
PS. If you amended your hypothesis to suggest that in generating ratings there might be a coefficient/multiplier applied based on quality - which means that if a 1* and 7* player did exactly the same things in the same match then the 1* might get a slightly higher rating - then there might be merit in that.
The only thing I don't agree with here is Nordeus people strike me as "cat people". I doubt, very much, dog licking comes into play.