If a 2nd Maunder Minimum causes a 2nd Little IceAge, will Warmists & Deniers unite to promote fossil fuel use?

No probably not. And it would be a travesty to a number of emerging 3rd world communities that stand to benefit from higher crop yields. The bottom line is there would be a drastic increase in energy consumption which would necesitate oil and other forms of energy development and deployment - regardless of who and what form is promoted.