Edexcel AS Geography Unit 1- What case studies do I need? Unhelpful teachers!

It seems you're well equipped with Hazard case studies, but I don't think you need so many Earthquake and Volcano case studies, its good t have some additional facts but a good case study knowledge of Philippines, California and another area, perhaps Bangladesh with suffice.

These are some others I'm learning, not sure if any additional are needed?
Africa- Climate Change
Arctic- Climate Change
They're both on the compulsory list for case studies.

Going Global
TNC- Walmart, Disney, Tesco etc. Any one will suffice
Could have a few examples of switched on and off places, to help discuss interconnectedness, countries in Africa and USA are classic examples
Poland to UK- Intra EU migration
Migration into Europe, illegal migrants and refugees(Syria/African countries)
UK to Spain- Ageing population
Mumbai and LA- are what I might use for case studies of Mega cities, but there are many others

My Teachers have also have been a bit under prepared when it comes to case studies too, and most of these I've learnt myself. Don't feel obliged to use these though, some may not have enough detail or too much as I've started to find out, so I may be changing some of which I use. Plus more recent case studies and unique ones may stand out in exams and earn the top band marks.
Hope this helps