This is great, thanks for sharing. So is the intention to manually sub to any you want?

Check out the community lemmyapps (not sure how to link yet), it has them all listed. I personally like Connect.

https://lemmy.world/c/lemmyapps

Two. One for lemmy.world but then due to the issues, moved to lemm.ee which is my current main.

There is literally a button to save posts, rather than commenting.

Yup, agree with this. I personally use Nextcloud but there are lighter solutions just for file hosting/syncing.