Take the subjects that your good at it and you have confidence! But also it must have sense to your aim...
sciences and maths
10
French students have the equivalent of the GCSEs.
You can go to college and take your GCSE's there.
Well, A-level is the more advanced, being taken at college or sixth form, afetr your GCSEs. However, your GCSEs are also important, as both employers and universities take your GCSE and A levels into consideration. It is common to take around 10 GCSEs and 3-4 Alevels.
Psycology, Pretty Good thing to take -nods-
A pediatrician is a doctor. You need to study medicine like any other doctor, so the same GCSEs as any other doctor. Maths, Chemistry, Physics, Biology.. any/all of these are important.
To become a lifeguard you need at least a+ to become a lifeguard.
7-8 is average, some schools will go in for up to 10. Usually kids with insanely high numbers of GCSEs do them out of school, or do them early. In some cases they speak a foreign language at home, so its easy for them. I wouldn't worry too much about the number of GCSEs you take, just make sure that you get good grades. Universities look to make offers based off your A levels anyway. For more information see How many GCSEs link.
Physics, maths. You probably need at least 5 A*-C GCSEs
You can try the Citizens Advice Bureau in Britain. They should be able to help you.
I assume you mean GCSEs Helpful would be Maths English Double-science or more But realistically it is more affected by your A levels