Not in the same way, but I have done this by adding a VCV OCT module to the V/Oct output of the sequencer, which then goes to the voice. Changing the octave on the OCT module changes the pitch of the notes being played. This could be done via MIDI by hooking into the IN on the OCT module.
I don’t know enough to say if this is the same as proper transposition.
Yes I’m pretty sure this would work with any piano roll sequencer. The Seq++ has transpose commands available with a right click on the scroll window but I couldn’t work out how to link that to outside.
Yeah, all those Seq++ commands like transpose, chop notes, arpeggiate etc… are “non real time”, and can’t be VC controlled. So your technique would have to be used with Seq++, too.