As I understand it, air at 70F has heat-energy in the form of kinetic motion of the air molecules but it also emits radiation as a black-body according to its temperature. My question is whether the distribution of energy expressed as one or the other form varies and if so what factors influence more radiation or more kinetic transfer. I would guess that dry air sparks more easily from static electricity because the current that "jumps" into the air is more insulated and therefore creates an intense temperature spike in a relatively small area (is this correct, btw?). So I would think that factors like friction of currents in the gas or liquid would make a difference, i.e. because friction prevents kinetic energy from transferring as easily, resulting in more radiation. But can you say that this radiation-potential is distinct from the increase in speed (heat) of the molecules due to relative insulation by their own viscosity? Or does heat sometimes get emitted more as radiation than as molecular motion or vice-versa?

The question is ill-formed. Heat is energy being transferred owing to a temperature difference; a body does not possess heat. The mechanisms of heat transfer are radiation, convection and conduction. The amount of transfer from each mechanism depends on the conditions. e.g. for a body in a vacuum, convection is not an option. For an isolated body, conduction is not an option. Radiation depends on the temperature of both the object and the surrounding reservoir.