Can customer accounts handle advance payments in Shopify?

Great ideas. I’ve been struggling with this, wondering if apps will mess up/duplicate customer or credit info. Dying for details on this. Which did you choose?

I get making the report from QBPOS (I have one), but where do you get the $$ to make the payment? Do you just discount by the credit amount?

I haven’t completed the Quickbooks connector, but the amounts obviously don’t carry over to Shopify.

Scenario A:

I like the custom payment idea, but how does Shopify let you close out the order?

Scenario B:

Can you issue gift cards for random credit amounts? Where do the funds come from?