Does your new server have the ability to support these old plugins at all? Doesn't look like it does.
The lua plugin system is well-developed and documented [1] so most plugins could be changed over easily.
- WorldEdit: https://forum.cuberite.org/thread-870.html
- Essentials: https://forum.cuberite.org/thread-1840.html
But also minigames like
- SkyBlock: https://forum.cuberite.org/thread-1508.html
- HungerGames: https://forum.cuberite.org/thread-1456.html
At that point, why not just switch over to Minetest? Given enough work, it could eventually be an attractive and feature-complete clone — and be nicely extensible too.