1.can hunters end their turn on the same space as another hunter?...
Yes, there's nothing in the rulebook that says a hunter can't share a space with another hunter. The character tokens are there for that purpose since it's hard to squeeze two minis in one space.
2.can hunters shoot through another hunter?..
Yes, they don't block each other's firing.
And 3.what is the order of how things happen?...for exp cobras ability to stun hunters if they end on him does that happen before the beasts ability to attack him?..
Cobra's ambush would trigger first which would prevent him from taking damage. Agent abilities generally happen before hunter abilities.