A point me and some friends are testing right now. Sentinel on WAR and on PLD don't effect enmity values of abilities.

How we tested:

We used a 3rd party member to grab aggroing(that is, just walked next to the mob) mobs to remove any potential bonus aggro for pulling. All tests were conducted with 0 +enmity gear. Target was Antling Diggers outside of Halatali(R43-46)

Baseline Test:2 WARs, both using Flash. No Sentinel.
WAR1(Me) used Flash after the mob was in range. Hate:WAR1
WAR2(Arioch) used Flash after. Hate: WAR1
WAR2 does 1 point of damage. Hate: WAR2

Interestingly enough, this shows that the mob WILL NOT change targets unless you go above the current enmity. Simplified, if WAR1 has 1000 Enmity, WAR2 must generate 1001 enmity for the mob to target WAR2.

Test #2, 2 WARS, 1 using Sentinel.
WAR1 used Sentinel before the mob was pulled.(To eliminate enmity gained from buffs)
WAR2 used Flash on the mob. Hate: WAR2
WAR1 used Flash w/Sentinel Active, hate did not transfer.
Conclusion: Sentinel as a WAR does not impact enmity gained by abilities.

Baseline 2: 1 WAR, 1 PLD.
Mob is Pulled by a pt member.
WAR uses Flash on a mob, PLD uses Flash after. Hate: WAR
PLD deals 1 point of damage after Flash. Hate: PLD
Conclusion: Hate values of Flash are the same regardless of Job, Flash's Blind Debuff does not accrue additional enmity.

Test 2: 1 WAR, 1 PLD, PLD uses Sentinel.
PLD uses Sentinel before the mob was pulled.(To prevent enmity gained from buffing.
WAR1 uses Flash when the mob is in range. Hate: WAR
PLD w/Sentinel active uses Flash. Hate: WAR
After Sentinel expires, PLD deals 1 point of damage. Hate:PLD
Conclusion: Sentinel does not affect enmity generated by abilities as a PLD.

Some other interesting things we found out.
Divine Veil: Has a high base enmity value.
Divine Regen: Hate generated by the regen actually goes to the person that CASTED the cure to proc the effect, not the PLD. I.E. WHM casts cure on PLD, divine regen procs on the 3rd party member. The hate from regen tics went towards the WHM's enmity instead of the PLD.