Welcome to Renoise!
I don’t have all the answers but for a couple of your questions there are 3rd party tools. If trackers scare you, then the following will too. Haha.
http://www.seankeisman.com/musicgen/musicgen.html
http://sector-seven.net/z/rpg/
http://renoise.hit.bg/
http://xrns-php.sourceforge.net/ (xrns_randomize)
https://forum.renoise.com/t/psymachine/20831
https://forum.renoise.com/t/xrni-microtuner/20702 (part of XRNS-PHP)
Good times.