For me movies are 1080p but for shows I’ve always scaled down to 480p with Stereo (now 720p after this thread). Space & compatibility across various devices are the main reasons. Really we don’t need 1080p quality for shows.
I’ve a fair bit of anime also both old (80s) and modern. Your findings are interesting and I’ll keep this in mind as I move forward.
On the normalizing 
I was looking at the link you provided above and also having a look at this thread Sharing some ffmpeg scripts I made to down convert audio in batch as well a 'night mode / DRC' and was going to start my testing using -filter:a "acompressor=ratio=4:makeup=2,loudnorm". Would this be a good starting point ? I’d like to not use ffmpeg-normalize unless I had to as I want to keep everything in the one ffmpeg command.
