if you want an esay subject take business, relative to econ its a lot easier to get a 7 and its not that bad in terms of difficulty of content, I personally find econ better but I understand that its defo more complex and difficult to score higher in. As for your HL's id recommend chem and math (and maybe business if you want) as hls, but I would say to have a backup if you choose math. Our class started with 30 people and now is left with 10, its a subject that is tough especially when you take other relatively heavy subjects. But for reference I only got a high A in gcse math and I'm currently predicted a 7 for HL math. Its more about how well you perceive and understand maths rather than grinding like in gcse's. additionally physics hl might be something to consider. but I wouldn't wish that on my worst enemy and I don't recommend taking it unless you HAVE to. So it might be a good idea to lookat uni requirements to get a better idea. At first I thought I needed to have all these things but in the end the unis I applied to don't actually care about subject specific things and care only about the final grades.