This is also something I do understand...
FSS says: Vulcanism - Iron Magma
What do you find on the surface: Iron Magma Lava Spout
I've already explained this, Magma is a subsurface feature, you will not see magma on the surface, you will see lava spouts, Magma, when it gets to the surface is called LAVA!
FSS says: Vulcanism - Silicate Magma
What do you find on the surface: Silicate Magma Lava Spout
See above.
FSS says: Vulcanism - Methane Magma
What do you find on the surface: Methane Ice Fumaroles
Correct, no magma, magma is a subsurface feature, when it reaches the surface it expresses a vapour or liquid, the methane ice fumaroles is the subsurface magma escaping from below ground and becoming a gas or liquid..
FSS says: Vulcanism - Water Magma
What do you find on the surface: Water Geysers
Correct, magma is a subsurface feature, when it gets to the surface it is geysers or steam.
So as you see, based on the Iron and Silicate phenomenons, I was expecting, to find Methane Lava Spout... But instead, I have only found Gas Vents and Fumaroles... The same with Water... I was expecting to find Water Lava Spouts, but instead you find geysers, the same like on a planet, where the FSS says "Water Geysers". So my point is, that it is pointless to go to explore planet, that says Water magma, in hopes of finding Water Lava Spouts, because there are no Water Lava Spouts, there are only Water geysers, even though the FSS says two different things for the same phenomenon...
The water in the geysers is the water lava, the methane when it gets to the surface as liquid is the lava. You are confusing yourself, if a body has water magma it will have boiling water as the lava, same with methane. Because we live in the earth the only phenomena we associate with lava is liquid rock, silicate lava, but liquid water, water geysers, is the lava of a body with water magma.
Also you are confusing two different types of vulcanism. When a body says it has a type of "magma" vulcanism it means it has a liquid core below the surface, and it's often this magma escaping that causes the geysers and other features. When a body just says "water geysers" it means there isn't a liquid core, the body is cold all the way through, like the moon and mars, the vulcanism on these bodies is usually caused by tidal stress from orbiting close to a binary partner or a gas giant and the heat to create the geysers is caused by tidal compression and stretching that heats fault areas above the melting point of the water or methane, which then escapes as gas or liquid.