I'm not 100% sure how to supply heat to my forges for glass, weapons, etc. I'm going to make a 3x1 pump stack powered with a water generator. However, I'm not sure exactly where the magma needs to go. I believe it needs to be an open space below the workshop (not covered by solid wall in the workshop, not in the center of the workshop). However, regarding heat: can I just make a long row of magma underneath a series of glass and metal workshops
(Disclaimer: I use Phoebus tileset.) If you look at a workshop just
prior to placing it, you will see which of the blocks are solid. They will be a brighter green X. The darker green are traversable. This means two things: Dwarves will be able to walk through the dark green X areas... and for magma-powered workshops, you must first channel holes underneath where the light green Xs are going to be. These holes must have a certain minimum level of magma underneath. The rest won't matter. (From memory, typically it is the center top square of a smelter, or the two mid side squares of forges.)
If I make a row of magma, will the tiles on top and below that magma burn? Let's say I had a realgar wall underneath magma, but I covered it with basalt flooring above... what about uncovered?
I'm not sure I understand the question, but if you build a floor
1 z-level over 7/7 full magma, you should be fine.
If I make a magma source for a wood furnace, can I use magma to create charcoal or ash? Would it thereafter turn to fire?
There is no need for a magma wood furnace, because wood does not require additional fuel to burn, it is the fuel.
Lastly, what I do instead of stack pumps is establish a mini-colony starting 1 level above the nearest convenient pool of magma. I usually have no shortage of haulers, so I set a small food and a small drink stockpile there that draws from the main stockpile, then I add a second dining room, then I set up a second quantum stockpile for all metal related items, and lastly I create nice bedrooms and move everyone directly related to the metal industry into the depths.