Double Degree vs Double Major + Honors?

Hey guys! I have a few questions:

For context, right now, I'm doing a double degree in Mathematics (Data Analysis and Operations Research) and Science (Computer Science). I just finished my first semester in a university ranked in the top 50 globally. I finished in the top 5% of all my classes, and I'm about to choose a major. My end goal is to do a Masters in Financial Mathematics at Oxford, and then onto a career as a quantitative trader.

Oxford requires the equivalent of an honors degree. For me to do an honors with a double degree will take 5 years. I could simply double major in Statistics and Computer Science under the Bachelor of Science and get an honors in 4 years instead, saving myself ~10k and a year of time. Will an investment bank look more favorably upon an additional year and an additional whole degree, or will they be impartial either way (meaning that I should in effect just finish in 4 years)?

Is a top 10 university likely to take in a top student from a low-tier university ranked ~50 globally? Is an investment bank willing to take in a top student from a low-tier university, but with a masters from a higher-ranked university, or should I consider transferring universities and moving to another state to have a bachelors from a higher ranked university (which won't be an option in the near future but if it is a deciding factor I'm sure I could work something out and organize credit transfers without increasing my time at university at all)?