The Netherlands, Belgium and France all accept the same adapter plug (type C/E/F) and you should be able to get hold of one fairly easily that has 2 or more USB ports for charging your phones.
https://www.travel-adaptor.com/europe/us/european-travel-adapters.php will give you the information you need and they are easy to find on Amazon and likely Canadian Tire.
That's the easy part. For the flat iron check to see if it's dual voltage (should say 100 - 240V 50 - 60Hz or similar). If it is make sure to get a decent quality adapter that is rated at 10A or so, some of the cheap ones are rated really low and can catch fire. If it's not trying to get a converter for power hungry items like this is usually problematic as most converters will only supply low powered items reliably. Flat irons tend to draw high amounts of current in their initial warm up.
The CPAP machine is the critical item. Again, you need to make sure that it can run on 230V 50Hz. If it doesn't you'll need to source a reliable transformer that is matched to the current draw of the machine. As it is used continuously for hours converters aren't usually a good option here and choosing something rated at about 150% of the machine's rated current is a rule of thumb. Unfortunately transformers are usually quite bulky and heavy. Worth doing some research here as it's obviously a critical piece of equipment.