Advice on Optimized Group Leader

[The Amazing Varnigan]

Pathfinder Prestige Class: Group Leader
http://www.d20pfsrd.com/classes/prestige-classes/other-paizo/a-b/bellflower -tiller

I want to build an optimized version of this class specifically to boost the abilities of the PCs around me.

I am thinking about taking a dip in Oracle Dualcursed Warsight for:

Misfortune (Ex): At 1st level, as an immediate action, you can force a creature within 30 feet to reroll any one d20 roll that it has just made before the results of the roll are revealed. The creature must take the result of the reroll, even if it’s worse than the original roll. Once a creature has suffered from your misfortune, it cannot be the target of this revelation again for 1 day.

Martial Flexibility: At 1st level, a warsighted can use a move action to gain the benefit of a combat feat she doesn't possess. This effect lasts for 1 minute. The warsighted must otherwise meet all the feat's prerequisites. She can use this ability a number of times per day equal to 3 + 1/2 her oracle level.

A dip in Cavalier for tactician

Feats and Items:
Battle Cry
Flagbearer + Banner of the Ancient Kings
Maybe Shield Focus and Covering Defense

Not sure which class to take levels in for the sneak attack though... any suggestions? Is there a bard archetype that gives sneak attack?

[Crie]

Best bet would be just do the three levels of rogue. You get some useful skill points, and it's the quickest progression to get the 2d6 Sneak Attack. Anything else will take something like five levels to get to that.

Really wanting to see an optimization of this class as well.