You're welcome to post your pre-sales questions here and we can clarify whatever you need information about :)
Yes, Vantage includes a custom form builder to which you can add other fields. This can be seen on the
Vantage admin demo site here, with more information also available on
this blog post/tutorial. On the form builder demo, you can select the "Text Area" option to add an extra area for paragraphs of text. The default form already has fields for images, so to add more would require additional customization, but can be done. Adding these fields does not slow down the site. Thanks.