I don't have any experience but would not plant anything edible in a juniper.
If you want to experiment, you might try herbals or an ornamental plant first.
It is an attractive stump that begs being planted in.
I don't have any experience with planting in stumps either. But what a beauty! I would try putting a Bromeliad (or several) along with the vine. Since it's out of the ground, I don't see why it would be a problem to experiment a little. Again, I know nothing but I think it would be cool.