It is possible to load documents from a database into Aspose.Word. You just need to get the blob field data, wrap it into a MemoryStream and read Document from the stream.
I’m not exactly sure about what you want to do with the data on your webform. Do you want to insert it into the document in some places? If yes, then it is possible to do using either MailMerge or DocumentBuilder.
Basically you can insert data into the document at merge fields, bookmarks and in other locations.
And yes, it is possible to combine multiple documents into one by copying or moving all sections from one document into another. You can specify that the section starts with a page break so the documents will be separated by page breaks.