It seems strange that for VSTis with multiple outputs (e.g. Kontakt) Orion has the option to reduce the number of outputs to only those you want to see in the mixer, however for the built-in synths (e.g. DrumRack, Pro-9, etc.) you have to choose up front whether you wish to create an instance with only 1 output, or a selection of other fixed output configurations (4, 8, etc.). So if you only want 2 outputs, you haved to opt for the 4 outputs option and put up with 2 unused outputs in your mixer. Or, worse, you start with the 1 output version, then realise later on you want to add another output but you can't. So you have to create a new track and migrate everything across.
It just seems that for the built-in synths it would be easier to make this totally flexible and just have one version of each plugin and the ability to dynamically add/remove outputs on the fly. Or, at least, offer the ability to reduce the number of outputs (i.e. hide outputs you don't want) so you can always create the version with the largest number of outputs and hide those you find you don't need.