Double character charge out of unit

strutsagget cited the relevant rules and thus answered his own question again: only one character can charge out of a unit. This is confirmed by

BRB Official Update Version 1.9, 11:
Q: If a unit containing one or more characters has had its Movement Allowance altered, will this affect a character leaving the unit, including if he tries to charge out of it? (p101)
A: Yes, but for that move only.

There is, as usual, no problem, if one applies the simple principle: unless specifically stated otherwise, normal rules apply. As strutsagget already quoted (BRB p. 99)

”Whilst a character is part of a unit, both he and the unit (including any other characters that have joined that unit) are treated as a single combined unit for all rules purposes, save for the exceptions listed here.”

Under movement, BRB p. 99 further specifies: "if the character is subject to any movement restrictions, then those restrictions apply to whole combined unit whilst the character remains part of it, and vice versa."

BRB p. 101 states: ”A character can charge out of a unit, by declaring a charge in the relevant phase – in which case, he will move and his unit will stay still – it is not permitted to declare a charge of its own, though it can move during the Remaining Moves phase.”

So, once a character has declared a charge, the unit becomes subject to a movement restriction, a restriction which applies to the whole combined unit - including any other character still part of the unit.

The same principle underpins BRB Official Update Version 1.9, 11:

Q: If a unit containing one or more characters has had its Movement Allowance altered, will this affect a character leaving the unit, including if he tries to charge out of it? (p101)
A: Yes, but for that move only.

You are overthinking things again. There is no need to get hooked on the fact that page 101 appears to talk only about 1 character in a combined unit, since the rules there apply to all characters in a combined unit. The whole page is about a character leaving a unit. Charging is juts one way, and it is the only way that restricts further movement by the unit he has left. All characters can leave the unit in the Remaining Moves sub-phase, before the unit moves and provided there are no other restrictions. 

The FAQ is clarifying a potential ambiguity on p. 101: "When leaving a unit, the character reverts to his normal rules for movement,"  and makes clear that any movement restrictions affecting the combined unit will still apply when leaving the unit. 

"A character" means exactly that - with the proviso that he is subject to any restrictions that apply. As already quoted above, BRB p. 99 specifies ”Whilst a character is part of a unit, both he and the unit (including any other characters that have joined that unit) are treated as a single combined unit for all rules purposes, save for the exceptions listed here” [Italics mine].  If a character charges out of a unit, then the rest of that unit is subject to a specific movement restriction, because of the very fact of a character charging out of the unit. It does not matter whether the remaining unit consists of a single or 100 R&F models, or a single or 100 character. 

You say:  "It's like if you rip one sentence out of a paragraph and then consider it to stand on its own - it will lead to too many misinterpretaions [sic]." And yet, you are doing exactly that. All that is written on page 101 is part of the rules for "Characters and Units,"  and has to be read in that context. Or to put it in another way: unless specifically stated otherwise, normal rules apply. 

Another epistemological discussion like for move/be moved? Thanks, but no thanks. The BRB is a rulebook, not a philosophical treatise. If some have questions like these 11 years after the book was written, perhaps the fault is not to be found with the BRB, but with themselves and their Cartesian anxiety.

While that is all true, this particular problem has been solved beyond reasonable doubt. Starting a discussion about what "a character" means serves no practical purpose.