--snipping--
1. The bunching was during the ballistic phase.
2. Sure. But why would you even try to bunch them then?
--end snips--
Without arguing too much, IIRC, even a full fleet formation is usually within 1 light second of each other for mutual defense, and with the downrange distances involved, the missiles HAVE to be bunched enough that targeting them during a ballistic phase becomes possible. Even at 20mm kilometers, you're a large enough fraction of the distance from Earth to Mars; any kind of great big loops in the missile path(s) by the SLN are relatively unlikely.
That said, I think that more accurately what Barricade would have done is break the signal lock of the SLN ships so that they might as well have been blind fired. I'm thinking back to the triple ripple, etc. that Haven used, by the way. Apollo makes many of those interception strategies moot because of the FTL loop, but Tremaine's ships are not Apollo capable.
That said... the Charles Taylors ARE big enough. It doesn't make sense that they wouldn't have KH-II and be useful as a control platform. Another plot-hole.