A fast food cafe in an estate can be a very profitable venture and also a very stressful one. In my opinion, as long as the estate is highly populated with the right crowds such as young people such as students and single men and women, there is huge potential.
But first things first, the fact that you have ready capital doesn't mean you will succeed, you have to do a thorough market research, projections and be sure of the source of your foodstuffs. Another headache is staff, you must have reliable staff otherwise they will enrich themselves at your expense. If you are in a 8-5 job then you are in for more drama.
The best option is to start with chips since it is fast moving and is eaten anytime by many. Preparation is also simpler. With time, you can add other foodstuffs gradually as you monitor your progress.
Also remember kanjo and health issues, fire extinguisher, garbage etc