This idea looks good. Finance revolves on information asymmetry and keeping your customer uninformed on what's best for them.

What does the final step on account opening and transfer of funds look like for the user? Surely banks can't be that cooperative in providing you an api to open accounts for them.

Are there any money market funds or short term debt funds in Mexico?

I am sure you would look into adding forex cards and remittances in future. There are a couple of startups here in India which help you get better forex rates by negotiating with banks for pre loaded foreign currency cards, hard currency and TT/Swift transfers.