Orbeon Forms for a regular web site?

Really a broad newbie question here so I apologize, but I wanted to ask:

Is Orbeon appropriate for use as part of a general web site?

e.g. Let's say an ecommerce oriented site where the general navigation and look and feel for the site is separately defined and implemented (but let's say it will read from eXist for it's product catalog), but let's say Orbeon Forms were used just for the forms to allow products to be added in the product catalog.

And let's say these product entry screens are required to have the look and feel of the rest of the site, and the same authentication, i.e. it's not acceptible for me to just run Orbeon separately on the side as an admin tool, it has to be integrated.

Specifically, I'm wondering:

a.  If the navigation/branding for the rest of the site were already done, using some templating scheme (tiles, sitemesh, whatever), could forms built with Orbeon Form Builder be deployed such that they could have their headers/footers/nav bar stuff applied with these other technologies?  So the form built with form builder appears inside the page whose navigation and branding around the edges comes from the other site (ideally without using a frame though I didn't think of that till now :).

b.  When I publish forms from Form Builder, the default Form Runner includes buttons in the button bar like the preview button and the PDF button that I wouldn't want.  Ideally I'd want to define my own button bar and control what buttons appear, what their labels are, and even the look of them (to match the buttons on the rest of the site).  Does Orbeon allow that?
 

Just noticed my subject line was misleading.  I know that Orbeon has a general XForms capability, but I was really asking specifically about using forms created using Form Builder in a general web site.

FWIW I have learned a bit more on my own regarding this e.g.:

a.  Using portlets to integrate things e.g. if the overall site were built on LifeRay Portal so the branding and navigation could be LifeRay and even use it's "themes".  

Anybody have experience with this?  Does form runner play forms built with for builder okay in Liferay portlets?  Any gotchas?

b.  I did notice the section on configuration which explains how e.g. to omit buttons on the "button bar" that form runner displays...  and how to override CSS style sheets...

But I didn't see anything about adding a completely custom button with custom behavior to the button bar of form runner.  Can this be done?