Triggering multiple MIDI sequences for live performance

Before I dig in and do some massive demo downloading, thought I'd see if anyone had any suggestions about the type of setup I'm looking for, using Audiomulch in a live laptop performance with various MIDI controllers.

I've previously used Hermann Seib's VST Host, so I'm basically familiar with the Audiomulch type of environment, but I'm a bit of a novice still. My setup involves using MIDI controller keyboards to play multiple VST instruments and adjust effects live, while manually mouse editing to trigger sampling and hold, reroute signal chains, and cue up samples played at various speeds. The only addition I'm looking for at this point is to be able to have separate and unrelated MIDI files on cue to run VST instruments - all within Audiomulch. I'm not really concerned about syncing anything since I perform mostly ambient music. The gist of what I'm trying to build is a setup that will allow me to interweave multiple MIDI sequences in a polyphonic/polyphonic way along with everything else I'm doing.

That being said, I'm also looking for something 'simple' that won't eat up too many resources as several separate open instances. The hypothetical MIDI player VST doesn't need to load its own VST instruments, although some have that function anyway. I have a PC, otherwise I'd seriously consider Numerology, but even that seems a bit overload, the more I think about it. Sugar Byes 'Thesys' or energyXT didn't float my boat upon previewing some videos. Phrazor looks to be the only option that seemed to fit my idea of a live working environment, beyond the more esoteric plugins like xoxos.

Multiple Reaper projects can be open simultaneously, obviously, and probably can be triggered separately after setting up MIDI Yoke, etc. That seems a bit clunky, but perhaps not so bad. Perhaps all I'm looking for really is just a VST plugin that loads and plays MIDI files, which I can record in Reaper. (Any recommendations for one?) Welcome any suggestions or comments.