As you said, these are all the pieces already. If what I'd figure is your question it's easy to answer:
"How much damage would I do if I fire for $Length time?"
$Length * $RoF = X rounds
X rounds * $damage = gunDamage
X rounds * $DOT% = avgDotAmount
DoTs are smart in this game, they all have their separate timers and can stack independently from one another. This makes the damage as intuitive as possible:
dotDamage = avgDotAmount * ticks(element)
totalDamage = (gunDamage + dotDamage) * multiplier(element)
As this was far too easy to answer, I can only assume your question would be like
"When can I stop firing, knowing that my DoTs will kill the enemy?"
To which the answer would be "Never, unless the target isn't currently affected, then keep firing."
To us human player at least; for all the data is there in the fountain of numbers that spew from the target you are perforating with bullets. Would we be perfect computers, we could see when a new dot starts ticking(it wouldn't have a previous tick before it) and thus know exactly how many ticks are left. Being human, all we can say is "it's on fire" or "it's not on fire." This makes knowing for SURE your target is going to die impossible, the best one could do is make a normal distribution graph(wiki) with the probabilities if your target will die.
If that's really what you'd want, I could run it through some model, but it's still gonna be a pretty useless graph. Input the specific gun and skills you're using, and you could get a graph with probabilities mapped vs dotDamage. Even if you could watch that while shooting things, you can only guess how much health your target has left.
If instead, and my final guess, the question would be "How much do I overkill?" that amounts to the same, as that is also "Amount of dotDamage still to be done."
It's an additional splash damage amount in addition to the weapon card damage. Percentages vary by weapon type.
Some Maliwan weapons list "Deals Bonus Elemental Damage" as an effect. These weapons deal an additional portion of elemental damage as splash damage around the bullet impact. The splash damage equals 50% of the weapon card damage for sniper rifles and Plasma Casters, and 80% for pistols; it is multiplied as normal for the element type, but is not further multiplied by critical hits or badass rank "elemental effect damage." Amp shield damage only applies on direct hits, and not this splash damage. However, the splash damage can trigger an elemental damage over time effect independently of the main bullet, resulting in double DoT triggers on some shots. This effect is especially useful on slag-snipers as the elemental explosion is guaranteed to slag the target even on a non-direct hit, as opposed to non-Maliwan sniper rifles that need to hit the target in addition to having only a reduced chance of applying the slag effect.
Rocket Launchers with "Deals Bonus Elemental Damage" are a special case. Whereas normal rocket launchers simply deal their weapon card damage as splash damage in a certain radius, DBED rocket launchers have two separate splash ranges. The smaller splash range deals 50% of the weapon card damage, and the larger splash range deals 25% of the weapon card damage. These stack, however, so anything within the smaller range is also hit by the larger range, resulting in a total of 75% weapon card damage on close hits. As with pistols and sniper rifles, these two damage effects can trigger the damage over time effect independently.
Source: Borderlands Wiki, "Borderlands 2 Elemental Damage - Bonus Elemental Damage"
Best Answer
No, falling never causes damage. However, there are places that result in insta-death if you fall there.
One good way to tell a fall will result in death is to pay attention to the map. If your destination falls outside the boundaries of the map, odds are you wont survive the journey.