No, this will not work.
1) Greater Bull Rush does not allow you to make attacks of opportunity against the target for the resulting movement. It allows your allies to make attacks of opportunity against the target for the resulting movement.
Benefit: You receive a +2 bonus on checks made to bull rush a foe. This bonus stacks with the bonus granted by Improved Bull Rush. Whenever you bull rush an opponent, his movement provokes attacks of opportunity from all of your allies (but not you).
2) Fortuitous only allows you to make ONE extra AoO per round at a -5, not 2.
This special ability can be placed only on melee weapons. A fortuitous weapon grants the wielder more attacks of opportunity. Once per round, when the wielder of a fortuitous weapon hits with an attack of opportunity, he can make a second attack of opportunity with this weapon against that foe at a –5 penalty.
Consider combining Thunderstriker with Eldritch Guardian. Get a mauler familiar. Take Paired Opportunists. You will end up losing 3 feats from your build (and bravery) but you should be able to do what you suggest as long as your familiar is adjacent.
One other thing I just realized, you cannot use a two-handed weapon while shield bashing with your buckler.
I know, it seems like the archetype should allow you to do so but during the two-handed weapon and armor spikes thread Jason Bulmahn basically said you couldn't (it is discussed by others for a few posts if you keep reading).
It really looks like the thunderstriker archetype intended for you to be able to TWF with a a two-handed weapon and buckler,but it doesn't have any specific rules text that allows you to.
Like Titan Mauler pre-errata, it's an archetype that doesn't do what it's supposed to do.
I bet the original version did, but was nerfed before publishing, so now it doesn't, but still has a lot of the set-ups for it left from back when it did.
I bet that's what happened to Titan Mauler too.
