Assaults and close combat

[AlienXXX]

Hello again.....

Narwan's reply to my previous thread raised a few more questions in my mind:
He mentioned that it is possible for a lone sniper, who has run out of grenades, to still assault a tank and take it out.

1) Does this mean that grenades are not required to assault a vehicle?

2) When an assault is unsucessful the assaulting unit never seems to take casualties, at least not from fire from that vehicle. Does a vehicle never attempt to repel an assault by firing on the attacking unit?

3) When I place a unit on the same hex as an enemy unit and do close combat, my unit never takes casualties.
I take it that units on the same hex fight "anything goes" including bayonets and hand-to-hand. Although I only move in when the enemy unit is either retreating, routed or has run out of shots, I would have thought that in the resulting fight my unit could still get casualties. Is that correct?

Let me have your thoughts, please...