These are good questions, but they're mostly not ones that can be answered by a bit of in-game documentation. Or even by a lot of in-game documentation.
- An extraction settlement produces what?
- An extraction settlement consumes what?
Odyssey settlements have selective markets, and changes to system variables, BGS states, etc. will reroll them. There's probably no more definite answer to this beyond "4-8 from this longer list of possible exports" that doesn't involve hundreds of pages of spreadsheet formulae.
- A refinery hub produces what?
- A refinery hub consumes what?
Nothing, refinery hubs aren't dockable (I wonder if they've fixed the build screen yet...) so don't have a commodity market service.
(This is the easy one)
- What are the ratios for what the market will supply based on how many settlements/hubs are in system?
Again this doesn't have a fully deterministic answer.
Grain, for example, is produced at between 7 and 172 tonnes per economic unit, and consumed at between 0.8 and 25t per economic unit. Exactly where any station fits on those ranges is (pseudo-)random (and again, appears to change as you change the system variables). So if you have two stations which are 50% Agricultural (produces Grain), 50% Extraction (consumes Grain) then it's quite possible that one of them will roll average-to-high for production and export Grain, and one will roll low very for production and import Grain.
There is no in-game guide of readable length which would allow you to answer that question. Even an in-game simulator of "what market will this station have if I add it now" won't usefully tell you what will happen to it 3 constructions later.
Ultimately if you want control over your market exports and imports, you need to ensure that you only build single-economy stations (which is not straightforward, and for some economies is completely impossible in the current model)
