Specific Flow for Shopify

[Dan54]

I am developing a private fulfillment app for our company and after reading through the api specs regarding fulfillment's I want to confirm I understand the "proper" flow for fully completed fulfillment's, and have a couple questions.

The Flow

1. Subscribe to the fulfillment webhook.
2. On receipt of a fulfillment, respond with a POST to /admin/orders/450789469/fulfillments/255858046/open.json to open(acknowledge) the fulfillment.
3. After shipping the item(s), update the tracking number(s) on the fulfillment with a PUT to /admin/orders/450789469/fulfillments/255858046.json
4. Complete the fulfillment with a POST to /admin/orders/450789469/fulfillments/255858046/complete.json.

The Questions

1. Are there shortcuts to this such as, can I set the status of the fulfillment to "success" in step three or does completing the fulfillment as in step 4 do something special to the fulfillment?
2. I presume that I will also need to assume that with the webhooks, we'll miss some fulfillment's. I was expecting to find an API that returns all pending fulfillment's but it appears that does not exist. Is the following the right way to retrieve pending fulfillment's?
   
   1. Request every order, see if it is in our system.
   2. If it is not in our system, then request the fulfillment.
   3. Enter the flow above at step 2.

Thanks for your input.