Identifying output from the (MS) xml parser

I am writing some C++ code to run under windows, using the MSXML DOM
implementation.
My user supplies both xml and xslt input.
The input may generate a new xml document, or a flat file.
I am trying to determine what comes out of the ms parser.  
Could someone(s) please advice me of the accuracy, or otherwise, of the
following statements?

I believe the output from the parser must be one of the following:
A result tree;
A wide (Unicode) string;
An ASCII (8bit) string;

I believe which of these is produced will be determined by the
<xsl:output> element.
Do I have to interrogate the style sheet to find this information?

If so, can I assume that the <xsl:stylesheet> element is the second node
in the xslt tree, or at least a top level element?

I believe the <xsl:output> element can only be a direct child (topmost
element) of the <xsl:stylesheet> element.  Could someone confirm this?

If the output method is "xml" or "html" the output must be a result
tree/xml document.

I have also seen an attribute of <output> called media-type, but have
not been able to find any documentation on this.  Can anyone comment on
this?

If the <output> "method" is neither "xml" not "html", then I assume the
output is a character stream.  Whether this uses 16 bit or 8
bit/multibyte characters will depend upon the "encoding" attribute.  Is
there a concise list of the "encoding" values that result in characters
of a particular size, or some other way to determine this information?

Thanks!!!

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