About Student X type issue

Thank you for answering my previous question ASAP, please I need to know the COST in Naira of applying for student X type at Lagos consulate and the cost of S visa for my baby.
2. Also, will I be able to authenticate my marriage certificate and baby's birth certificate at Lagos consulate office?.
3. Lastly, is it only the foreigner physical examination form I need to take along for the interview or all the results inclusive (because I already sent the results to the school in China while applying), do I have to do the physical examination for my 10 months baby also? Thanks