If you plan your major work, then History Ext. shouldn't be a problem work-wise. An added bonus? It's the most interesting subject you'll do at school.
Eco is no problem. Read the textbook. Regurgitate.
4U English requires a lot of planning as well, especially as History Ext. and 4U are due around the same time. My advice? Actually start the fuckin' things more than a week before they're due.
Anton