Realtime Sampling Device

I am beginning creation on a sound installation and am looking for some technical advice. I've used Max in the past but would consider myself a beginner (everything I have made has been fairly simple - see links in my profile).

Here is what I am trying to accomplish:

1) take in audio from an external mic (and hopefully multiple mics once a prototype is functioning)
2) chop a section to be used (potentially based on a quality - like % change in amplitude of signal)
3) analyze it for the dominant pitch (or as an alternative, create one with a sharp band pass filter??)
4) assign it to a MIDI pitch within a Sampler
5) apply it to a preexisting MIDI composition as it is playing
6) have the process automated and loop every so often in order to have the textures change while the melody stays the same

The idea is to have external environmental sound textures attached to composed melodies real time. These textures would be processed via the steps above and then played into the gallery space.

The process above is just how I am thinking about it right now so if there are any other ideas of how to accomplish a similar result in a different method, feel free to share.

Relevant info or preexisting code would be greatly appreciated. Thanks!