All of your pathways are impressive and all will get you on to an economics degree. It sounds like you have your heart set on a Maths subject and a Science subject as well as Economics, so I would go with the second pathway, so you can include something a bit different in there to show that you are well rounded academically.
However...
A word of warning - I picked Economics, German, Maths and Theatre Studies at AS-Level, and dropped German this year. Language A-Levels are not for the faint hearted! I got two A*s at GCSE in German and Spanish, yet scraped a C in my AS year. It's difficult, and you have to put way more work in than I did! If you think you'll be okay with this then great, but if not, why not take a 'softer' subject such as Psychology, PE or Theatre?
As a general rule, I think two 'hard' subjects, a 'soft' subject and an arty subject are the way to go. Economics and Maths are obviously hard, French is arty (and hard!!) so if you've definitely got your mind made up on Economics you might not need a science? Something to think about anyway. Hope I helped (and haven't completely confused you!)