Because both of those affs can be cured in the interim (either by passive curing or by a really conscientious ally) it's better for you (or one of your own allies) to gust the insta-killer out if you cannot escape yourself.
Yes, the right amount. And Hallifax has definitely been moving in the right direction (imo) regarding this, in things like moving for the "no shouting" law to be removed, among others.
Yes. You'll stay at Master in Knighthood. You'd only have to forget Stag (or Moon), basically -- and even that's not painful because the Stag lessons go into the same pool you can learn Crow (or Night) from.
The running idea behind Taint and geomantic taint (imo) is that the Taint had Kethuru's full and undivided will behind it, and the taint is what happened when Kethuru stopped having a use for it/was distracted/was defeated. The Magnagorans that were…
As I understand it, an activated colossus (i.e. just the colossus and the heart inserted) will generate a small amount of passive points AND reduce the value of enemy bombarding. Possibly enhances your own bombards too -- not sure on that part thoug…