Hi FD...
The Canadian guidance that I provided earlier is operational in nature. That is, it is only applicable to the interpretation of the operating regulations here in Canada. Your local CAA may or may not have provided similar guidance or interpretation...
The certification requirements that I have mentioned are harmonized on an international basis and are applicable throughout most of the world. Therefore, the testing done in accordance with 25.803 - Emergency Evacuation is the same for Airbus, Bombardier, Boeing, Embraer, etc. They all build their aircraft and test them to the same standards so that they can be sold and delivered worldwide.
Does the inclusion of three simulated infants reflect
any number of infants? I don't have a good answer for that one... The test criteria was established quite a while ago, when aircraft were obviously smaller. If I recall correctly, I think that when Airbus conducted the evacuation demonstration for the A380 they used more than the three mandated. So basically, I would suggest that the limiting factor on the number of infants would be the safety and emergency equipment available.
All that being said, your company should have established and published this minimum acceptable number based upon the configuration and equipment available on each of your aircraft types. Some companies may not accept more than "220" passengers, including lap-held infants. Others, may accept 15 lap-held infants in addition to the 220 passengers as they have sufficient emergency equipment to accommodate them.
How this impacts directly to the occupancy of the rafts, I'm not entirely certain. They are designed to accommodate an overload but I don't immediately recall how infants are calculated in the numbers. I'll have to see if I can dig that up.
The other question, that panda-k-bear responded to regarding the exit types, evacuation flow rates and configuration, can be found at the following link to the EASA certification requirements:
Certification Specifications for Large Aeroplanes CS-25
If you search down for
25.807 - Emergency Exits you will find the definitions and descriptions for each type of exit.