First, thanks for the kind words! We're glad you're liking Octavox.
I'm guessing when you're referring to the feedback loop, you mean the "all-encompassing" loop for all eight voices, since there is feedback available for each individual voice? I certainly think this is a good idea, but at the moment we're swamped with a huge number of projects here. However, I'll log this here as a feature request, and we'll definitely consider implementing it when we have time.
As per your second request, it sounds like you want a way to control the delay times in each voice via a keyboard, is that correct? While that feature isn't available, as you mentioned you could set multiple 'Current Snapshots' on a particular preset to different delay times, and then automate the switch between presets to achieve the effect.
Thanks for the cool audio demo as well! We'd certainly like to see the collection of presets you're working on if you'd like to share.