After a few hours of hacking and trial and error, it seems there is also a file named Sandbox_config.sbc that also needs to be edited. I basically downloaded the entire save folder and grepped for any instance of <EnableIngameScripts> and found a 3rd occurrence of that string in the Sandbox_config.zbc file. So, I changed it there and re-uploaded everything and re-started the server, and now I have scripts. So, I guess this one can be marked as solved.
Hello! I've set up a new server and have about 10-12 hours into a world and realized I never enabled in-game scripts. So, I did the normal stop the server, download both the savegame sandbox.sbc and SpaceEngineers-Dedicated.cfg files, edited them and changed <EnableIngameScripts>true</EnableIngameScripts> in both files, then re-FTP'd them up to their respective locations on the server, and finally started the server. However, when rejoining the world, I still don't get the edit scripts button showing up in programmable blocks. I DO see a list of pre-defined scripts (I'm assuming base game scripts) available in a list inside the programmable blocks, but no "Edit" or otherwise buttons appearing. Have I possibly done something wrong?