As I noted, there doesn't appear to be the Lutheran paradox of the dual universality of grace and the particularity of election in Peter. This was even more strongly confirmed by his remarks on Paul's statement "God wills all men to be saved." He follows one interpretation of Augustine on this point. Augustine had several. In one version, Augustine said that God meant all "sorts" of men to be saved. So African, white, and Asian. This is of course not what the verse says at all. Augustine's second interpretation which Lombard cites and agrees with is that God wills all (meaning the elect) to be saved. That is, he "all that are saved are ones that he wills." This even sillier.
Moving onto book 2, Lombard describes the fall of the angels. Satan could not have been a sinner from the beginning- since God does not create evil. Some authors of the period apparently thought that God had created Satan to "make sport of him." They relied on the old Latin version of Job where there is a reference to God "making the dragon so that he might make sport of him." I assume, though I haven't done this research, that this is a translation of those passages where God says that Leviathan is his pet- in other words, Satan isn't being referred to there, but probably some sort of pre-historic animal that was still around at the time of Job.
Anyways, Peter agrees with Augustine that angels were created good, yet they had not been confirmed in the good. Humans are the same way. Adam could sin even though he was morally perfect. In heaven when we too are confirmed in the good, we won't be able to sin. Similarly, it doesn't appear from Scripture that the good angels are ever going to fall away, so it's logical that the situation with them is the same. Most Lutheran theologians have followed Augustine on this point.
Now, according to Augustine and Lombard as well, there was a sort of moment after the angels creation when they could choose God and be confirmed in the good- meaning they would receive the ability to never fall away- or for them to be proud and revolt. Satan and his angels choose the later, whereas the good angels choose the former.
But why did some choose one course and not the other? Augustine and the Master of Sentences agree it had to do with grace. God had predestined the good angels to be confirmed in the good and therefore gave them grace to this end. He didn't predestine the bad angels so hence they fell away. They weren't capable of doing this because God refused to give them grace.
Now this may sound very unfair on God's part, but Peter insists (against Augustine it seems- since he provides no proof text, and I don't recall this from the discussion of the fall of the angels in book 9 of City of God) that the bad angels could have at least chosen not to fall. I suppose it would be like saying that they could have chosen to at least put the car in neutral and not reverse. Without grace, they couldn't have chosen forward drive. Lombard now goes a step further: If they had at least chosen to stay in neutral, God would have rewarded them with grace and given them them the ability to move towards confirmation in the good.
Now, here's the problem. Peter doesn't think human beings have the ability to do what is within them for gaining grace. He's quite clear about this. But do we see at least the beginning here of the "do what is within us" to gain grace that Luther rejected? Perhaps, but that would take more research. At the very least, it seems that Lombard accepts the logic of this position that got Ockham into trouble to certain extent.