The difference between conventional and non conventional energy resources is that conventional energy resources are much more common. An example of a conventional energy resource would be oil, a non conventional energy resource would be solar power.

Examples are Coal, natural gas, oil, firewood and hydro

The main non-crude oil is Natural Gas Liquid. Other non-crudes include condensates, non- conventional liquids, and refinery gains.

Synthetic and conventional oil can be mixed and used with no problem. That is exactly what a synthetic blend that you can buy is. A mix of synthetic oil and conventional.

There is no absolute hard and fast definition. But I would say coal, oil, and natural gas, and hydro are conventional. Wind, solar, tidal, and biomass non-conventional. I'm not sure about nuclear.