Enthalpy of combustion releases heat and exothermic.
Enthalpy of solution can be positive or negative depends on the substance.
Enthalpy of reaction it also be negative or positive.
Enthalpy of atomization is always positive because energy is required to break bonds and form free atoms.

Potential energy is due to position.
Electric energy is due to electric current.
Total energy of system consist of K.E and P.E which is called Internal Energy.
Kinetic energy is due to motion.