Slitherine

"No BG can pass through a BG that already passed through it this phase." (p46). My LF have withdrawn behind my advancing HF. In his next Impact Phase my opponent charges my HF and breaks them in his Melee Phase. They rout and burst through my LF. My opponent's initial pursuit reaches my LF who evade. As per the above rule they can not interpenetrate my routing HF.
a. Do they evade to the point where they touch my HF and then halt with their backs to the enemy?
b. If my opponent can still reach them with his variable move pursuit does he charge into them?
c. When my LF roll for their evade move, does my opponent get an additional variable move roll?

Thanks. Terry G.

The important words in this situation are "this phase".
Your LF withdrew behind your HF in your turn
He charged your HF in his turn - which is quite obviously a different phase (and a different turn.
Your LF can therefore evade through your HF.

A battlegroup never gets more than 1 variable move in a phase.