Q.Are pyrotechnics necessary for lifeboats and life rafts? If Yes, then how many are there ?

refer to LSA code 4.1.5 Equipment (for life rafts) and 4.4.8 (for life boats):

10. four rocket parachute flares complying with the requirements of section 3.1;

.11. six hand flares complying with the requirements of section 3.2;

.12. two buoyant smoke signals complying with the requirements of section 3.3;