Although not stated, is it possible to bunch up the three objective tokens? It does not say anything about keeping them spaced apart.

Yep.

After placing obstacles, the second player places 3 objective tokens in the setup area beyond distance 4 of both players' edges. Then the first player may move each objective token to within distance 1-2 of its current position

They can be stacked directly on top of each other if you like.

But your Enemy has the say on the final placement. They could move all 3 together, or decide to distance 2 them apart, or whatever...

As long as they are legally placed, in the setup area, beyond distance 4 of both players edges - its gold.