As said, Dreamweaver is just a code editor, and is handy for editing any code, such as Drupal or WordPress code—if you happen to be into editing that sort of stuff.
I've heard that Apple doesn't support Flash
Again, as said, Flash works fine on Apple desktop devices, but it isn't supported on the iDevices ... which has basically put a stake through the heart of Flash ... at least the mobile versions.
And what about web-based fonts? I think Adobe has two or three separate font programs, but I wondered if WordPress or Drupal might have their own font programs.
Don't confuse programs with the fonts themselves. For a long time, websites could only reliably use fonts that end users were likely to have already installed on their computers. Now you have various options, like linking to online services—like Typekit, Fontdeck, Google Fonts etc. that serve up the font files remotely—or uploading the fonts to your website and letting the end user download them ... although you can't do that legally in many cases. (A site like FontSquirrel has many free fonts available for use that you can upload to your website and link to via CSS.)
Yes, TypeKit is pretty cool, and I was impressed to discover that it comes as part of the Creative Cloud without paying extra. That has almost won me over to sighing up.