Yes, you can download an active customer credit note PDF from the customer credit note details.
See below for an example of the downloaded credit note.
Yes, you can download a refund advice from the customer refund details.
See below for an example of the downloaded credit note.
Yes, there are a couple of ways that this can be done:
Via custom fields - See Custom Fields for more information.
Adding a logo to your customer credit note - You can do this by setting a unique logo in PDF Templates. Head over to Settings > Templates > PDFs > Choose a Template > Header > Upload Logo.
The downloaded PDF will display amounts based on the currency of the customer credit note.