Just to clarify, from a support standpoint this would be Ignite/Elemental Proliferation, Combustion, Bonechill?
What about duration modifiers, such as from Swift Affliction (Edit: or efficacy since I forgot that exists) or all those uniques and other such modifiers? If I fire an arrow not supported by swift affliction, then pummel the enemy with swift affliction arrows, will my burn duration be fixed to the first explosion, or will it be independently tracked so that the burn damage reduces in the last second or so when the swift affliction ones run out? Also applies to people with different durations in a party, but I imagine the coding would be identical since it's all just ailment duration stuff.