I would like to answer your last question first. Yes you can create compositions very fast. And editing those sequeunces is quite nice as well. But the fact that you've been spoiled by Cubase you may be disappointed with how editing is done.
For example: I just discovered that the copy event command not only copies, but also functions as a cut and paste function as
There is a lot inside the QY70. There are things that can be done that you don't see right from the jump.
To answer the first question, the QY70 will transmit on all of it's 16 tracks/midi channels. Realise though, that if you use a track to send midi you have to mute that track in the QY70. If you don't the current sound on that track will sound as well. It would make for a nice layering effect.
I should point out that once midi is set for out going transmission, the midi info is always sent. In other words, You cannot specify which tracks transmit midi and which ones don't they either all do or they all don't. Not a big deal because when you mute a track it only mutes the internal voice not the midi info
When you use the QY70 live along with phat boy (this is a box full of knobs for controlling the filter, resonance, release, attack etc. on the QY70 or any device that receives continous controller information. It works great with the PMA-5 also). Where I'm going with this is you can do filter sweeps live with Phat Boy hooked up to the QY70. And the QY70 will record this information as well. You could record effects level changes, volume level for each track etc. You could even enter your samplers sysex info into the QY70 and have the QY70 plat it back. Or the QY70 will record sysex data directly. It's pretty amazing. There's a lot under the hood.
I should point out that it sounds very analog when it needs to.
Here is another thing that I forgot to mention in the other forum. The QY70 has a nice feature the PMA-5 doesn't an undo command.
Give it a try you'll be surprised at the power awaiting you.