How do banks and fintech's issue credit cards on the back end? I'm looking for very granular steps.

The White labeling in business financing is a business model that allows companies to offer financial services or products under their own brand ¹ ² ³ ⁴ ⁵. Here are some key points about white labeling in business financing

There's no way to guess about this, as checks will vary across time. For example, you might get a Barclay Apple card + they might check Transunion today + Experian tomorrow or both. There's no way you can form any conclusion about this, which will last more than a few days.

I don't think there's a best practice, similar to how much you should charge for your B2B SaaS company, cause it really depends on the market size, cost to deliver, and perceived monetary value you're offering via your API. That being said, the way I've baselined any pricing for my products has been to look at 100 companies that share similar customers and pricing model and either look on their website or email their sales team and ask directly. Even if you get 10% response that's enough to get you started.

Setup your business as a pass through. You run the transactions + charge a fee. Likely, for the businesses you mention, they'd be happy to pay a premium fee... as you will be the only payment processor to accept their transactions.

It is difficult to provide an exact number as it would require an audit of all stripe merchants' systems to check for dynamic billing descriptors enabled and their equivalents.