battlenet whisper forwarding?

[Saqor]

jamba does it.

http://www.curse.com/addons/wow/jamba

the other thing is it should the last char logged in.

While I can't say I've made a rigorous study of it, I agree with the OP in that it seems random who it'll register as the "active" char. Pretty annoying, though Jamba does take care of it most of the time.