1) Can the enemies move past one another and can they fire arrows past one another.
2) Can characters do any of the stated above?
3) Is there any rule for which enemy units you spawn first? I have found nothing that suggests how enemies are spawned or by strength or type.
I really think the rules are lacking in this game and need some serious clarification.
1/2) Allies can move through and have Line of Sight through other allies. So enemies through enemies and heroes through heroes.
3) Spawning order is intended to be random so you would just roll them all and start placing them. If you wanted to make it more or less difficult you could choose the order if you wanted.
There are updated rules available online already and we will continue to update and clarify things as they come up. If you have any other questions just let me know!