Hi there,
We actually encountered the first use case described and have created a solution for it with our app called Tryon. Our app basically allows merchants to offer a ‘Try Before You Buy’ experience while we maintain an authorization hold on the customer’s card and we manage all the communications with them via emails. After the customer’s pre-defined trial period is over, you as a merchant can update at the app about what was returned and we capture the necessary funds based on an automatic calculation of the costs of items the customer kept.
You can check it out here: https://apps.shopify.com/tryon-try-before-you-buy
Would love to hear your opinion and help you with anything that’s needed.