**1. Do I need to call the parent constructor in B's constructor to initialize the value owner in A**

Unless you are passing arguments to a constructor, you do not need to explicitly call it. Assigning ` owner = msg.sender` will be evaluated when the contract is deployed

**2. Does B need its own address, or will it just use A's as its own?**

Using Inheritance in Solidity will bundle your code together and deploy it under a single contract

From the [solidity docs](http://solidity.readthedocs.io/en/develop/contracts.html#inheritance):

>When a contract inherits from multiple contracts, only a single contract is created on the blockchain, and the code from all the base contracts is copied into the created contract.