Forgive me for my BAD English. But I really wonder if I've got the plot right

1) In Tjolmar, I heard that Ingramosch(dwarf prince) brought lots of dwarf workers here,
and nameless one's temple is under the Ingramosch's house.
So Ingramosch built 'temple of nameless one' right? (or just built house and vault over the temple)

2) In Lovangen, some people said Ingramosch had been Ailian's colleague.
But Ailian stole the salamander stone from player, and if player don't get back salamander stone from Ailian(in 10 days?), you'll lose to the cult of nameless one(?)
Um... So, I think Ailian is cultist(nameless one's)

3) According to 1), 2) Ingramosch looks bad guy. he is cultist(suspicious..) and he have ignored the orc intruders.
BUT why he should have been perified in the nameless one's temple?
Arkandor(dragon) said "As long as you have to deal with me, Ingramosch will remain a hostage to my friend!"
It is weird...why Ingramosch was held hostage UNDER Ingramosch's house??? I don't understand what's going on here.

tl;dr
if Ingramosch is good guy, why he built house over the temple? and why he had been in cahoots with Ailian?
if Ingramosch is bad guy, why elves didn't claim that? why he was held hostage?

Am I missing something? Could you please enlighten me?