If the barrier of Vegeth was not effective against the absorption of super buu, I think the salvation of the universe would depend entirely on the Kaioshin's and Namekian.

At first, they would try to be desire with the dragon balls the disappearance of super buu, but it certainly would be beyond the capacity of the dragon...At second as they would try to teleport the earth in the sun to completely destroy super buu, but they would fail because super buu has the teleportation and the barrier from Vegeth.

The second wish would be a barrier that prevents to feel auras around the Kaioshin's planet, and before zen buu can teletransport to namek(because zen buu would understand that the cause is the namekkian dragon balls), they would wish that all namekkians going on the kaioshin's planet.

Now namekkians haven't more desires, and being in a place not accessible by normal teleportation, probably would unite into one super Namekian and than would use the potara to fuse with kibitoshin.

In the following two days they would study the tactics to eliminate buu without being absorbed, the high Kaioshin develop the super namekian strength with his ability and than would begin the hardest battle ever seen in the universe.