I am a keyboard player in a traditional music duo. Our act travels all year round and instead of bringing a 88 key fully weighted keyboard on the plane, we usually have it backlined. The problem is that the condition and type/model of the keyboard provided varies. Most keyboards have midi capabilities but the quality of the piano sound is sometimes very poor. I was looking into using a virtual piano through midi for our live performances so that our sound would be consistent no matter what keyboard is backlined. Specifically the Ivory ii Grand Pianos I am wondering if this would even work? (i know that you need different drivers for different keyboards) And if it is a good option, how to set it up for a live performance setting? I would be using a mac.
There is one part of your question that I am qualified to answer, and that is the part about requiring different drivers for each keyboard. This would not be the case unless the keyboard in question was being plugged directly in to your Mac via USB.
If you add a MIDI interface to your setup, then you only need drivers for this interface, and you will take it with you wherever you go. The MIDI cable you use to plug the keyboard into your interface only sends MIDI commands, and this is a standardized language that is not manufacturer-specific.
The only thing you may need to troubleshoot is matching the MIDI channel being output from the keyboard to the input channel on your sampler. But 9 times out of 10 this will work without any issue; only if someone has made specific changes to the keyboard would it not output on MIDI channel 1 by default.
Someone else's answer will need to go into detail about the software you are using since I am not familiar with it, but you should also consider a safe performance setup for the Mac that is hosting. Simple things like turning off sleep are just the tip of the iceberg -- there are a few different changes you can make to ensure your performance is consistent and uninterrupted (some more important than others). I will reference this guide for a fairly extensive overview:
The article is a few years old and some things (like the fan controller modification) are a bit overkill in my opinion, but it's a great place to start.