I didn't find any documentation to support that S3 Glacier is a supported target nor that it isn't. S3, however, is a valid target.
When S3 Glacier is the desired target, can we transfer directly to it, or do we need lifecycle policies to achieve this behaviour?
From my previous projects, it transfers to S3 with
Standardstorage class.What you have to do is to make a transitioning s3 lifecycle from what you have thoughts.
Still, the best way of uploading to
Glacieris over S3 storage classes, you can check John's comment about the reason behind: Uploading files to Glacier using AWS S3 v/s S3 Glacier upload