Draft licensing and attribution captions for mixed-source images

A blog post uses three images from three different sources:

1. An Unsplash photo (license doesn't require attribution, but we like crediting
   photographers anyway).
2. A photo from Wikimedia Commons licensed CC BY-SA 4.0, which requires
   attribution and a link to the license, and imposes share-alike terms on any
   derivative.
3. An in-house photo we commissioned from a photographer, all rights reserved,
   used under our own contract.

[replace with your own three images and their actual license terms]

We cropped image 2 to a square aspect ratio for our layout. Write:
1. An attribution caption for image 1 (optional but included) in a shorter,
   lighter format than the required one.
2. A required attribution caption for image 2, including photographer/uploader
   name, license name, and a link to the license text, formatted the way CC BY-SA
   actually requires it.
3. A flag on the crop: does cropping image 2 count as a derivative work under
   BY-SA's share-alike clause in a way that affects how we can license our own
   page, or does simple cropping fall under normal fair-use editing? Tell me which,
   and if there's any ambiguity, tell me to caption it as "cropped from original"
   so the modification is disclosed either way.
4. Confirm no caption is legally required for image 3, just an internal usage note
   for our own records (contract reference, usage rights expiration if any).