Woah I'm surprised your school is making you do four. Even though I did four, the vast majority of schools are said to be cutting down to 3 for the years after the guinea pigs (our year
but we're coping... ish).
1) I don't really cope doing two essay subjects, but doing maths makes it so much more bearable because it requires different thinking skills. The best way to approach having a majority of essay subjects is to understand the detail first, particularly for politics you can get so involved in the debate you lose grasp about what the actual theory is. Also, reading is the way to understand a topic. When you do your coursework it is much more like university work than previously. So in my case we had about 4 weeks of lessons to get a grasp of witchcraft and from July until now we've just been researching and reading loads of books. I think I've read about 6 whole books on witchcraft by now and my bibliography is massive.
Not only is reading essential for the coursework, but also the examined units. Textbooks distill information, if you want different interpretations, commentary, examples you
need to read extra. The 'Access to History' books are fantastic, because they're concise yet really detailed. I bought a whole load of political autobiographies at the start of the year and I think I only looked at Thatcher's book once for some environment stuff. So I don't recommend that kind of reading for politics, instead the news is best. Getting the distinction between history and politics is really important, politics is a contemporary subject so it is so important to be up to date with the news and not be using examples from the 18th century!!
2) I do Edexcel, studying Nationalism in 20th Cent. Europe (looking at Germany and Italy), Tudor Rebellions and Witchcraft! I'm so jealous you're focusing on political history, I really wanted to do the Parliamentary A2 unit.
3) The subjects I have chosen are fantastic for a course like PPE. I would say if you can, pick Maths, Politics, History and Economics if you continue all four subjects to A2. But if you think you'll drop a subject after Y12, pick Maths, Politics
or Econ, History and maybe a science. The simple reason is they really value Maths and History, leaving you to drop either Politics or Economics - but it would look rather weird applying for a degree which is 1/3 politics, yet you have dropped politics!