Comparing Redshift against Hadoop+Hive is reasonable. As you pointed out... the technologies are very different. However, there is a large overlap in use cases.
I strongly disagree. I am (or was) using both Hadoop and HBase and they are useful for very different purposes (huge amounts of nonstructured data, possibly with difficult-to-predict use cases versus structured data).
Also note that Hive is just a layer over Hadoop with DB-like syntax, it doesn't make Hadoop a DB. It is still running MR queries beneath it.