The exoflame should be be able to power the heater, or a block could be added that is enabled alongside botania being present that uses mana to make heat, a manasteel heater basically, as a side grade to the iron heater

Why would you think this is useful? A burner is not a furnace, using heater to heat burner has no advantage at all.

To clarify, the problem with this is hard to implement. We must have a same metric for fuels in both exoflames and burners.