Hello. This build is not practical as a villager anything but I had fun making a Sulphur Plume machine that is compact and simple. I realize that it will be some time before we get to use Sulphur on Foxcraft but that does not mean we can't share some ideas.
This build uses 5 observers, 2 dispensers, 1 button. (optional 1 redstone dust if you choose)
Press the button, lava is dispensed, observer detects lava and triggers other dispenser to place water. There is a reason for 5 observers and that is timing of the villager falling. Once a villager is on top of a Sulphur plume it will be 7 blocks up so when the lava is removed the plume disappears and the fall will damage it. Thus with this setup the villager takes no fall damage, there is just enough delay. (only necessary if a villager is your choice for this build)

This is how it looks activated with no villager. Now to build the tube for the plume and villager.

When making the tube it is important to place a block above the villager and even more important to place it at the 9th block up from where the water is. The reason for this is because the villager will bounce on the plume and if the machine is activated while the villager is at the highest point of his bounce then it will still take fall damage due to the water being gone before it lands. With the block above him in this position the villager has no room to bounce.

Here is what to do if you want to have a floor at the height that the villager is standing. This is why the redstone dust is optional. From the villagers feet the glass goes up 9 blocks.

That is about it, pretty simple build that works flawlessly. I did try it with a pressure plate but ran into an issue. If the pressure plate is triggered to fast in succession then the water and lava would go out of sync.
Don't use wood in the build too close to the lava for obvious reasons. Piston cannot push a Sulphur block.

Works with any work station. I was hoping the shelves would be a useful way to display what the villager is trading but not so much when they trade something for emeralds. Like this guy here - 3 different trades for emeralds, 1 with iron, then diamonds, then flint. hard to make that make sense with just 4 shelves.
Hope this helps, have fun out there.
This build uses 5 observers, 2 dispensers, 1 button. (optional 1 redstone dust if you choose)
Press the button, lava is dispensed, observer detects lava and triggers other dispenser to place water. There is a reason for 5 observers and that is timing of the villager falling. Once a villager is on top of a Sulphur plume it will be 7 blocks up so when the lava is removed the plume disappears and the fall will damage it. Thus with this setup the villager takes no fall damage, there is just enough delay. (only necessary if a villager is your choice for this build)

This is how it looks activated with no villager. Now to build the tube for the plume and villager.

When making the tube it is important to place a block above the villager and even more important to place it at the 9th block up from where the water is. The reason for this is because the villager will bounce on the plume and if the machine is activated while the villager is at the highest point of his bounce then it will still take fall damage due to the water being gone before it lands. With the block above him in this position the villager has no room to bounce.

Here is what to do if you want to have a floor at the height that the villager is standing. This is why the redstone dust is optional. From the villagers feet the glass goes up 9 blocks.

That is about it, pretty simple build that works flawlessly. I did try it with a pressure plate but ran into an issue. If the pressure plate is triggered to fast in succession then the water and lava would go out of sync.
Don't use wood in the build too close to the lava for obvious reasons. Piston cannot push a Sulphur block.

Works with any work station. I was hoping the shelves would be a useful way to display what the villager is trading but not so much when they trade something for emeralds. Like this guy here - 3 different trades for emeralds, 1 with iron, then diamonds, then flint. hard to make that make sense with just 4 shelves.
Hope this helps, have fun out there.