I can't answer all of these, but here are a few:
AS has a SD co-efficient of 0.143 per hit target, thus each 9 points of SD equals 1 point additional damage on the target, or 1.9 additional threat.
Seal of the Crusader scales a bit depending on gear, but on a typical tankadin setup, you're looking at no more then 7% increase on your default attack, not to mention the loss of threat from Seal of Righteousness or Seal of Vengeance.
Judgement of the Crusader, at L70, without additonal gear increases, increases Holy damage taken by up to 219. This works the same as spell coefficients. In effect, when attack that target with Holy Damage, you have an additional 219 SD. This equates to 27 more damage per tick of max level consecration, 31 damage to a target hit by AS, or an additional 36 holy damage per swing of a 1.8 speed mace.
Blessing of Sanctuary generates, with 0 SD, 87 threat per block. I don't know how much it generates when you apply it to a target.
If you have precision, not at all. I don't know how well spell hit scales, but it isn't that good, considering with precision, there's only a 13% chance to miss at all. However, our main threat spells have excellent SD scalage, especially consecration, that has a SD coefficient of 0.952.
To give you some numbers, an additional 10 Spell damage will give you:
2.261 tps from consecration.
9.88 threat per holy shield block
~1 threat per Blessing of Sanc Block
13.87 threat per JoR
These numbers are before any additional buffs and/or talents (except Imp Righteous Fury).
Edit: Err, sorry, didn't notice the bit about 450SD. You should be able to scale from what I've said to 450.
