Your post is a little hard to follow, but I'll take a stab with a few comments. And I assume you mean Zurich (ZRH)?
1) Yes if you book via AA you cancel for a credit, even for codeshare flights on BA metal. No idea what BA or IB's current cancelation policy is.
2) Depending on the specific fare, fare basis, and routing, you may earn more (or less) Loyalty Points booking via BA or IB compared to AA. This would be the only reason I can think of to book via a partner, assuming the fares are the same.
3) Cancelling and rebooking your awards on AA metal out and backsounds great but have you actually priced this out? For example, AA wants 300k miles per person for a one-way DEN-PHL-ZRH in business on your outbound date. Not surprising as this is peak season. This would be a non starter for me.