I came across an overview of employees (including demographics such as gender and migratory background) provided by the employment agency. Unfortunately one needs to pay 36 EUR to get it. Please check the following Excel for more details.
And there is another source that might be even more helpful. Check https://www.regionalstatistik.de. The topic number 12 (Bevölkerung) includes some of the information you are looking for. Have a look under Statistik 12411 (Fortschreibung des Bevölkerungsstandes).