Is it safe to remove this mod mid-save? Considering all of the additions are separate from the main factory I assume it would be, but I'm not sure how your implementation works and if it might leave anything behind.

As long as you are deliberate about it, yes; e.g. do not remove it while you're inside a Sandbox. Mods have no ability to run code when they are removed - so there's nothing I can do to clean anything up; you've have to do anything like that on your own.

is it possible to remove the tabs in other? in the map view, for example the personal and multiplayer sections

After removing the mod, you can use the editor mode to delete the surfaces.

A small addition: for those who use a custom patch that keeps achievements enabled with mods, and using /editor disables them -
1. add Editor Extensions mod
2. disable Blueprint Sandboxes
3. restart, load game with not syncing mods.
4. use EE's hotkey to turn on editor mode, it will prompt you in the chat/message log, I think it's Ctrl+Alt+E
5. delete the extra surface
6. save the game in different slot for safety
7. disable EE, restart, play
Achievements should still be not disabled after loading the modified game.
So far it worked for me, the thing that disables achievements in Factorio is not the editor itself, it's the console command /editor you normally type