On the new class features:
The O-bard can take a feat to swap majestic word for Skald's aura, old druids can spend a feat to swap a daily power for a use of summon nature's ally, while a new druid can spend a feat to get wild shape and can trade a use of summon nature's ally for a daily power. The witch adds a new cantrip to the mage's list of options. For the barbarian it's picking either set of features, no swapping.
However, all the powers are reverse compatible (although some power may not be useful without some creative usage. A barbarian would need to get access to some other defender's aura to benefit from some of his powers, the O-bard would need some basic attack and/or the skald aura to make use of most of their powers.
Paragon Paths:
There are only 4 in the book, each exclusive to the 4 new builds in the book. They are presented seperately from the class, after all the classes, so less like an essential book.
Fey gifts:
Most are similar to the Scent of Gold, a kind of minor ritual that you can cast for free. The one that could have the most obvious actual use is the ability to turn a nonhostile tiny natural beast into a mount until your next extended rest. But none are particularly combat useful.
The two handed weapon feat is a traditional expertise bonus to hit and +1 untyped damage per tier when charging.