yeah, most benches get unlocked in the order you need them.
furnace early. about the time you are looking to make steel, you probably want 2-4 furnaces. but, dont really need more early.
blacksmith for iron weapons/tools. correct.
Thralls asap as well yes.
Which thralls is probably the biggest thing to consider, since they are not clearly locked by level and feats.
Thralls have 4 main effects, depending on level, and type.
They reduce crafting time. increase burn time. Reduce crafting cost. and provide specific recipes.
Reduced crafting time, gives faster turnaround,a nd reduced fuel use.
increased burn time, reduces fuel use.
Reduced craft cost is one of the bigger ones, as it well, reduces craft cost..
Check the wiki for each.
smelters increase burn time, and speed. so arent that great. again, a second furnace does that job really. only increases fuel eff. oil, coal, dry wood too common to care.
Carpenters/blacksmiths,alchemist,armorer can get 25 and 50% reduced cost however. That shit is huge.
carpenters also do both carpenter bench, and artisans table.
so at least t2 of each of those, should be high priority.
Tanners also just give increased burn time, and reduced craft time. so, dont effect how much leather/tar you get, but will increase burn efficiency. Bark is a much more annoying fuel, then oil/wood/coal. so that is at least a little bit relevant.
Reduced costs, round down to nearest whole number.
Example. T2 blacksmith reduces cost by 25%. An iron reinforcement is normally 2 iron bars for 1 iron reinforcement. 2 reduced to 1.5 is rounded down to 1.
A t2 blacksmith will make iron reinforcements cost 1 iron bar.