I don't really think this is the right place, you could have asked this in the RP Q&A. Being an avid lightning user, and one to have studied the element extensively, I see both sides in the argument, I see how the manga/anime tends to conflict our reasoning from before or what we thought at one time. First, the manga does some inconsistency within elemental and jutsu interaction (no not plot holes, keep that shit out). But actual jutsus and elemental stuff there are some exceptions being seen in the anime - especially when filler comes into play - and because of this we need to not take a couple situations off and change the entirety of what we thought before so soon. We need to take something and keep it solid until we have clear cut, consistent, evidence that proves otherwise for us. In this case, lightning interaction with water.
There is two types of lightning, focused and unfocused. Focused generally has a shape, is condensed, has tangibility, and is quite lethal. Being of how compressed that lightning is, it wouldn't make much sense for water conducting it, its too constricted for it to be that way. So I am in full agreement, we can use focused electricity in water. Now what is focused? By manga definition Chidori has a very advance shape to it, more so then any other lightning jutsu (the majority at least) so being able to use it underwater is completely plausible without getting shocked. But it isn't a good example to use as something to say we can use lightning underwater so easily, it is at the end of the day, an extremely advance shape and would likely remain condensed in place. The same goes for the Raikage armor, it has suck an insanely condensed shape, he can literally penetrate through solid material with ease with just a couple fingers, it is shaped tightly around his body, and is an armor that moves along with his body movement. So that isn't a good example, its focused lightning, there shouldn't be a reason for it to be conducted.
Unfocused lightning is the real issue. That is the lightning that has no shape, its just a current, consider something like nagashi for example. If I was to create an unfocused current around my body in water, I should be shocked. This form is less controllable, and is naturally able to conduct water. A good rule for thumb to tell if the lightning is unfocused is simply to ask a few questions: Does it have an advance shape? Is it condensed? Does it spread around when released? If the answer is usually, No, No, and Yes. Then most of the time its unfocused lightning. With this form, I don't think it is viable at all for us to be able to use it within a water source, especially if we create the lightning on our body and attempt to move it outward, the lightning will be uncontrollable and conduct on the water naturally, and go against you. So I lean towards the illogical form of it, I don't think it would work well.
I'm also a firm believer that if unfocused lightning is being conducted under material already, it likely won't detach itself from its first conducted material to be conducted on something else. What does that mean? Take a Kunai with electricity and drop it in water, either the lightning will remain with the kunai, or leave it and conduct on the water. I'm not sure to be very honest the result, but I would lean under just whatever conducts lightning the best, or what it was conducted on first. Since we can't really take Naruto example, real world says metal conducts lightning much better, so I would assume it wouldn't switch.
Now lets take those examples you had.
Anything that has something to do with the Chidori is negated most of the time as I first explained, since the advance shape, and meant to remain close to the arm/hand, it won't have room to conduct in water. So you could use chidori underwater.
The armor of the raikage is the same thing, it stays tightly around his body along with other things I mentioned.
There is not enough water in mist at all to conduct itself, you could use unfocused and focused in that source it doesn't matter as much.
The one where Sasuke used the lightning sword and release his lightning, firstly, it was aimed at the source and to move forward. Also, I might be seeing the pic wrong, but the lightning doesn't even touch the water, it seems to move up and forward. But for the sake of debate lets say it does, he aims it to go forward, the lightning originated from his sword and not his body either, so there would be no way for him to get hurt. And just as I said before, it is already around a sword, metal conducts electricity better, so if he was to dip it in water the end result will either be it stays on the sword or some electricity is scattered, but even if it scatters, it is moving forward out of Sasukes reach, and he is holding it by its safety hilt.
The cloud ninja is similar to the above. Look at his hands, those are spheres of lightning, that seems quite the shape, and then he has the currents to move outward. The current is unfocused, but the lightning around his hand is shaped, so he would be safe, plus he directs the lightning away from himself. It does seem the most iffiest, but at the same time, even if it seemed like unfocused all the way, it doesn't seem like a viable situation to completely rule under that we can use lightning underwater without some sort of serious effect.
Lightning Release: Lightning Land Spikes (Raiton: Raikou Riki Kasui)
Rank: A
Type: Attack
Range: Short-Mid
Chakra cost: 30
Damage points: 60
Description: The user channels chakra through their feet. After the user had channeled the chakra into their feet, the user stomps their feet and sends the lightning chakra into a desired area. The lightning shoots up in that area without warning making between one and eight spikes. The spikes can go through flesh and numb the target body for one turn.
-Only used three times per battle
-Chakra Sensors and Chakra read Doujutsu Users can sense/see lightning.
Aww the issue of an old school technique. This is tough to judge. Firstly, it originates from his body, specifically the feet, so a false move would put him in danger. Lightning does not appear out of nowhere- it needs to travel through a medium, it doesn't just appear out of thin air or anywhere, a lot of the time its the ground cause unfocused lightning can actually travel along ground, in this case its water, so the lightning moves from his feet to the area of attack. So here is the thing, the lightning coming out of his foot, is it unfocused or focused? It doesn't say at all. I would personally say it can go anyway, but since the lightning chakra seems at its purest at this point, it doesn't seem to have any sort of serious shape or tangibility, it seems to have at most regular lightning chakra, which is unfocused (or pure) at the beginning until we put a shape on it. Pretty sure Kakashi said that.
Anyway, this is just my perspective, its an old tech which I'm not sure which way it can go or be finalized. However, my conclusion is we should use focused lightning on water, and avoid the usage of unfocused.
P.S. I always thought or believe that those who specialize should be able to use lightning underwater without issue. Pretty sure nagashi won't paralyze movement of people if they specialize in lightning, at most just pain, probably a cool benefit if you are from Kumo or advance with lightning.
I'm out, I know you guys hate my wallie z.z but I was bored and pulled an all nighter again
