Plan file naming and folders for a bulk media import

We're migrating 400 images from an old CMS export into WordPress ahead of a site
relaunch. The export folder is a mess: filenames like IMG_2039.jpg, scan001.tif,
Untitled-14.png, and a handful of Cyrillic-alphabet filenames from a translated
version of the site. They cover four content areas: blog post headers, product
shots, staff headshots, and PDF report cover images.

Give me:
1. A naming convention (pattern, not just examples) that works across all four
   content areas, using lowercase and hyphens, with enough specificity that two
   similar images (e.g., two blog headers about "email marketing") don't collide.
2. A folder or tag structure inside the WordPress media library to group these by
   content area and, ideally, by publish year, since editors will need to find a
   specific 2024 post's header image again without scrolling through everything.
3. A flag for the one case that needs special handling before any bulk renaming:
   roughly 30 of these images already rank in Google Images under their current
   ugly filenames and are driving referral traffic. Tell me how to identify which
   ones (cross-reference against [replace with your analytics image-search report])
   and what to do so renaming them doesn't silently kill that traffic.

[replace bracketed details with your own export inventory and site structure]