It looks like you have a lot of different needs which may be best served by different products. Small static sites can probably be well served by shared hosting plans. Larger sites with ecommerce may require a bit more careful approach than a virtual server with a bunch of other services... If I were you, I'd separate business-critical sites like ecommerce from the rest.
For the business critical sites, I'd use DreamHost Cloud, putting different services on separate servers: SQL database on one server, frontend on another... I'd also invest time into configuration management tools like ansible.
For blogs, I'd save headaches and use DreamPress: let someone else deal with security upgrades, fixes, operating systems upgrade, speed optimization etc. Customers will be happier, too.