10. Similarly, if we choose to play a madhyalaya gat instead of, or followed….

Similarly, if we choose to play a madhyalaya gat instead of, or followed by the vilambit, would the speed be determined by one's ability to play taans in double laya?

If we consider thumri-numa ragas like Pilu, Khamaj, Tilak Kamod etc., the vilambit gat is usually omitted unless one has the mijaz and capability to develop light classical music vistar. Otherwise what you mention would be correct. However don’t forget that classical music is governed by munde munde matir bhinna (different people, different approach/attitude).