i want to see if these \"build a . . .\" flash sites (to support a user customized ordering process) are done using regular flash or Flex?
The first site you linked is especially quite nice - you can tell the programmer put alot of work into it.
Have you worked on Flash before? The reason I am asking is because it is quite a different beast - requires both left and right brain to fully grasp. If you are just starting and want to build a site similar to the ones you linked then I will recommend 'pure' Flash with CS4 (or 5 if you can afford it). Reason being that Flex (now called Flash Builder - no confusion there haha), is really geared towards building form based websites. Yes, you can build other Flash type animations in there but its much harder to do (well), than just using Creative Studio.
Now, you might find that you eventually want or need to use Flex, but trust me you can build an entire web page with just Creative Studio complete with interaction and complex navigations. Here are some sites that may help you in your task (which is a large one btw!):
The second site has alot of tutorials for things you will need, like how to build menu items and buttons, and also how to handle user interaction (mouse moves, drags, key clicks etc). Your also going to need to know ALOT of ActionScript. Here's a good reference for that:
It's unfortunate you cannot use HTML 5 for this project. Making a major investment in learning Flash seems like a waste of time to me. But hopefully the links provided help you in this task and please make a comment if you need more info.