I doubt that Uristiel can do and arm that fortress that fast even if we convince him. Most likely he will spend huge amounts of mana on the combat, and rituals take time (and crafting takes even more time) . While dwarf god will make the fortress, we will gather build the tree, gather Mana and then, together with Krait lift the fortress into the air using newly received mana
I'm not sure; talk with Uristiel before guessing what his capabilities are. He's had months with little to do, probably letting mana stockpile for when it could help...
Oh, and villagers inside the fortress = destroyed village, destroyed economy.
It worked for the real world. And no; the most important things are the people, and who says we can't move parts of the economy (whatever you mean by that) onto the castle with the peasants?
Anyways...yeah, add touches to the Castle. But we should have the Castle, for
when we get attacked. With some good design and Bread Lichen, we can stay there a looong time, until the Justicars grow wings.
My Plan
1) Fly to Urist together with 2 dragons and 200 firejackets, provide fire support, spend at most 47 mana on the battle
2) try to convert as many surviving orcs and goblins as we can ( Fortress will need garrison after all)
3) Ask god of dwarves to build the fortress
4) Return home and spend 250 mana (+mana we got from new worshipers, if any) to raise the tree
5) Next day, with fresh income go and raise the fortress into the air (we'll have exactly 300 mana)
This plan sounds OK...if the math works like you said it will. Be a bit more conservative with the numbers* and sure.
*Say, only 200 mana on the tree.
Oh, and our ally have perfect scouts, why bother to make our own?
Because we're idiots.