Confirming: CS is fully bufferable from A+BA. You can input the command from the start. More than that, you can actually input B+G within the move and it'll come out at the first frame possible after the end of A+BA.
As for BB, AA, 2A, similar to SC4 -- buffer somewhere along the tail end of the move.
This should help people wondering about how fast should the input be. Basicly when you press 28 she will step with in that step buffer the rest. If done fast enough she will step then run forward a bit and then CS come out.
Also the Range on CS is very good. don't know if JF has an even bigger range. Will post video soon.