Rio Linda refers to a low-end suburb of Sacramento, CA where Rush originated his current show format. People from Rio Linda were pretty dense and didn't "get" Rush's humor and references. A person "from Rio Linda" is someone who's totally out of the loop.
The Reisch thing dates to the first Clinton administration. I've never figured out any reason for the exaggerated pronunciation beyond the fact that Reisch is a very arrogant, self-important little man. Rush is giving him mocking "respect."
This one developed because Rush saw Reich introduce himself by stressing the soft "ch" ending with such exaggeration as to be annoying. I believe Reich did/does it to get people to stop pronouncing his name with the hard "ck" ending, reminding people of Nazi Germany. But Rush back when said that he heard that, rolled his eyes and ever since, pronounces it over and above to yes, mock Reich.