A61
I can't find any mention of it in the rules. Closest thing I found to grapple and polymorph is the Tenori monk, that is able to prevent creatures from polymorphing in a grapple.

A62
Maybe. It seems to be confirmed for some undead, others are unmentioned. It also depends on campaign setting and even personal view, but lets avoid making this philosophical.

By the fluff in the books there are a couple of intelligent undead that have souls. Liches have bound their soul to an item to achieve immortality. Ghost and other incorporeal undead are described as lost souls (There is a small line in the GameMastery Guide even), stuck between this world and the next. Vampires in the Golarion setting also seem to have souls, as stated by The Great Beyond.

There is also the side note that when your body is transformed into an undead, you cannot be resurrected, even by spells that offer a new body (Reincarnation and True Resurrection). So being undead has some influence on souls and their ability to return the mortal plane, but whether that means if the soul is trapped inside the undead, or just stuck in the afterlife is unexplained. Again The Great Beyond calls out that unintelligent undeads, like skeletons and zombies, have no souls. so make of this what you want.