Hi No 3
Your question is so wide ranging that whilst I am sure many of us would be pleased to help you it would take hours to cover all the potential issues.
The flambe method is the first variable and following the principles of prevention the first step you should take is to eliminate the risk of fire- do you need to use flammable liquids such as meths, or is there a safer way.
Secondly, if you are stuck with the process, identification and control of all combustible materials in the vicinity is the next step.
But even with the best control, things can go wrong so consider what will happen if there is a fire. How will people get out if there is a fire? Can they turn their back on a fire and walk away from it to a place of safety. If they cant, or have to pass the flambe area to reach an exit its a no no. Are all exit routes clear, marked, unobstructed.
How will the alarm be raised and will the flambe cause false alarms
What fire fighting equipment is available and is it suitable for flammable liquids, has the chef been shown how to use it.
No doubt others will come up with other suggestions in addition to these.
Good luck with the project