Hey there,
and thanks for your comment. I hope you’re doing well today.
To 1: Yes, that’s correct.
To 2: Hmm… are you currently using this schema for your WooCommerce product? It should load the desired status, price and SKU when you visit the page (or when you check it with the structured data test tools) with the parameter. The page without the parameters always just loads the default data.
To 3: I’ve just entered the URL in the schema.org validator (click here) but it doesn’t strip the parameter.