As someone who likes to follow geopolitics, I can't help but wonder if the timing of this extradition request was strategic. When Meng was arrested, Canada was in the middle of NAFTA/USMCA re-negotiations and our Prime Minister was publicly musing about diversifying our trade partnerships, specifically focused on engaging with China. The automatic arrest of one of China's "royals" per our extradition treaty with the US was an extremely effective way of erasing our only major leverage on that negotiation.
IIRC the charge of bank fraud for business dealings in Iran was largely unrelated to Huawei's (sketchy) telco business. Kind of like how they got Al Capone on tax evasion.
[1] https://www.nytimes.com/2018/12/12/world/asia/michael-spavor...