1. Have you register with BEM?
2. Problem will arise if you register with different discipline. ( BEM very strict), must be from same discipline..anyway you can take the professional interview, even you are pass, you can't register with BEM as professional engineer.
3. If you plan to take IR under electrical, you have to take additional papers related to electrical, so far you can do it in UNITEN.
4.It's not necessary to have approval for mechatronics design or anything related to mechatronics,  the main job of professional engineer is to ensure the safety.