Alright I'll try to put it in a nautical sense or something idk.
I'll start with water since it's the most logical beginning. Fire's marriage with water is quite a simple one really, as the former is weak against the latter. Water is wet and puts out fire when it comes in contact with it. Water and Fire when combined either when colliding with each other or working with each other will generally have an effect of steam coming out of it. Most of the time if the fire compared to the water is tepid enough it will heat the water to the point of making it similar to a sauna but you can also make it hotter boiling your opponents alive. When on equal calibre, say B-Rank Water against A-Rank Fire, it will evaporate into a hot steam which covers the battlefield if it's big enough. This can potentially burn anyone in the area or could be used as a pseudo mist technique.
When combined with Earth, it's all different and depends on the substance given by the earth seeing as we have different variations of the Earth jutsu like Swamp of the Underworld, and other solid jutsu. Fire is neutral to earth, but I've found Earth can be used in conjunction with fire to make a type of lava. With the fire being superheated enough, it would be able to break down the earth and combine with it, taking the plasmatic state of the fire as well as the solid state of the earth and transposing it into a liquidated state which is quite handy. This is unlike Lava Release used by Kurotsuchi and Mei where for our version it's needed to create seperate techniques before making the lava. In the state of Swamp of the Underworld where the earth is already in a liquidated state, it would act more similarly to the Water release, boiling the swamp first before it completely transforms into lava, though I imagine the speed of creation would be quicker.
When used in conjunction with Lightning, it creates something very unique. From your mention in the quote before, they are both elements in a plasmatic state, and coincidentally both "yang" elements. Also as you mentioned and I'm sorry for stealing a lot of this from you but you put it so well, they're both able to keep up with each other in terms of molecular structure. They both compliment each other with their weaknesses (lightning < wind < fire). One thing I find interesting is the plasmatic state of the two elements which allow them to be used so well together. Because you're able to make the element itself intangible you can also create some interesting combos. With the fire element coming first, you can launch something of a wall towards them which is widespread and so on. Following up you can use a lightning technique spear to drive through the fire in order to hit the target. This is intended for them to initially defend against the fire but then the lightning comes first and stops the first defense from happening.
As such, even though they are neutral towards each other, they are most definitely not the best thing to defend with against their techniques.
Wind is probably the most common one we see in our RP with Fire. The element is considered weak against Fire for it's pretty much adding fuel to the fire. Though in that lies how Wind can fight against the element. Fire is composed of three objects which it requires to keep going: heat, fuel and wind/oxygen. When the Wind element is combined with fire, it will strengthen the flame by fuelling it's power and thus making it bigger. But when opposed and the two elements are clashing, Wind acts as a defuser of sorts, trying to blow out the fire like a birthday child blowing out candles. Because of this, an A-Rank Wind technique would be enough to cancel out a B-Rank Fire technique. To be honest I'm not entirely sure of what the aftermath would be after Fire and Wind collide, just a hot wind area type of thing?