Shopify - Capture Payment on Fulfillment setup and process

Integrating Shopify with NetSuite and looking for information on how to setup capturing payment based on fulfillment. 

Configuration so far in Celigo for Billing Flows:

• Auto-Bill Orders in NetSuite when Status = Pending Billing
• Capture order payments in = Shopify after the order fulfillment

Configuration in Shopify:

• Payment Capture switched from Automatic (Capture on Order) to Manual (authorize on order and capture on Fulfillment)

My question is does the NetSuite Billing to Shopify Billing (add) flow trigger the actual payment capture in Shopify? 

What if the original authorization has expired, does shopify try to reauth and capture at this time?

What if the card is declined and capture cannot be completed, what is the process to reconcile?