What about a pinned leaders, 1FP half squads or vehicle crews in CC? They can still make an attack. Very low odds against anything more than themselves but they can still do it.
Yes, such attacks can be made in CC since those attacks are based on a ratio of attacker FP vs defender FP but on the IFT 1FP is the minimum firepower required to be able to attack.
Smalles attack possible is 1 FP, if reduced to less than one there is no attack opportunity. Unless you got Assault FP capability in the AFPh that is as that ould give you a minimal FP of 2 FP.
But several newbies have expressed an interest as to why their FP isn't halved in defence. I haven't a clue, really, but it strikes me as the sort of thing that could quite often be altered by a house rule.