Overseer helps Avast detect common (technical) issues with their products. In a sense, it behaves similarly to the Avast Emergency Update but is able to correct these issues independently and even catch them sooner.
aswbIDSAgent is the Behaviour Shield process.
avRepair has been explained by mchain.
On top of what mchain has said about the Emergency Updater, it can also fix problems without requiring a full program update.