Protection Skill Stacking Question

Suppose I have a damage preventor, such as Life Bond, on a team member. The skill description says I take half the damage, and X amount is prevented. Now, suppose I put Shielding Hands on the same team member. Is the initial damage divided in two, with me getting half and the other guy getting half, then each damage portion is reduced respectively (by Shielding Hands for the other guy, by Life Bond for me)? Or is the initial damage reduced by the Shielding Hands amount, then I take half of what's left, which is then further reduced by Life Bond?

To make this more concrete, suppose Life Bond reduces by, oh, say 10 (I'm not sure if this an actual attainable value, just using it for simplicity), and Shielding Hands reduces by 5. Team member gets smacked for 50 damage. Is the resulting damage I take going to be 50/2 - 10 = 15 (with team member taking 50/2 - 5 = 20), or (50-5)/2 - 10 = 12.5? Or is it some other combination?

Similarly, if Protective Spirit and Shielding Hands are on the same person, is the 10% max damage calculated after the Shielding Hands prevention amount is subtracted from the incoming damage, or is the damage first reduced to 10%, then SH is subtracted? Suppose I have 400 health, Shielding Hands prevents 10, and I am hit for 50 damage. Is the Shielding Hands amount subtracted first (leaving 40), then filtered through Protective Spirit (meaning I take all remaining 40 anyway), or is it first reduced by Protective Spirit, then by Shielding Hands (for 50 - 10 [= 40, which is 10% of health] - 10 [Shielding Hands] = 30)?

Oh...and do spells such as Retribution trigger off damage received by spells such as Life Bond?

Depends on stacking order. If you casted sheilding hands first it would be (50 - (SH amount))/2, and you get the same, minus your amount from protection spells. If you cast SH second they would get (50/2 - (SH amount)) and you get 50/2 minus the amount from protection spells.