Your cookie lifespan is 60 days, does this cover subsequent purchases or only the first purchase?
The cookie is there for the first conversion. Afterwards, your customer is your customer. So you earn aggregate commissions on your customers.
How are commissioned activities reported?
Inside the dashboard, there's a report. You'll see a running tally.
Are commissions associated to a particular banner and/or referring page?
No. they're aggregate. Net sales, minus any discounts a customer might take advantage of, as well as taxes and shipping.
Do banners reside on our server (our control), your server (your control) or either at our option?
They're hosted with our shopify app. You export code to put on your site. Embed the code. Banners hosted on our account.
If you need a custom banner we can create it for you, and wrap your code around it.