Changing into other VST-Instrument over time?

you could duplicate the same track, put a different instrument on each, and fade one out as the other fades in. what else may work, but i'm not sure, is that you can assing FX to individual itmes, so you could potentially split the item, overlap them with a crossfade, and apply the FX you want on each one and they should blend together. this might be more annoying if you're going to add more items, because you'll always have to go and assign FX to every new item in that track. that's a great idea though, i never thought of that. could be cool.

If those VSTi's have a volume knob, perhaps put them both on the channel, make an action to control the volumes, and set up a rotary knob or fader on your controller to control both volumes? Knob more to the left or fader lower = more from VSTi 1, knob more to the right or fader higher = more from VSTi 2. Just an idea ;)

Making two tracks would be the easiest solution I guess. I'll try the other options when I have the time. Thanks for the answers.

Looks good, I'll try it. Seems to be exactly what I've been looking for. Thanks!