If a fear causing unit charges a unit fighting in a close combat in the flank, does the charged unit take a fear tests, then a panic test?
Yes, when you charge it takes a fear test. If it fails it must roll 6's to hit you. If it passes they fight as normal. Then, if you win the combat, it takes a break test. Remember that you get +1 for charging the rear/flank and he gets no rank bonuses!
No, if a unit is already in CC they count as Immune to Psychology and do not have to take a fear test (or terror for that matter). You never have to take a panic test if charged by an enemy, that rule doesn't exist any more in this edition.
Aye, page 48 in the BRB under Psychology Tests & break tests: "...units engaged in close combat and fleeing units never take psychology tests (panic, fear, terror and stupidity).'