Can :packages and :headers arguments in latex SRC blocks be made affect EXPORT blocks of results?

[hugo]

tl;dr: can I have `:packages' and `:headers' arguments from LaTeX src
block take effect, when I export those blocks as export blocks?

I wanted a way to write tikz snippets inside org documents, preview them
in the document as images, but have the tikz /code/ appear when I
exported to LaTeX. So far I have this:

,----
| #+header: :results (if (org-export-derived-backend-p 
org-export-current-backend 'latex) "latex" "file raw")
| #+header: :file (if (org-export-derived-backend-p 
org-export-current-backend 'latex) nil "foo.png")
| #+header: :packages '((nil "tikz" t))
| #+header: :imagemagick t :fit t
| #+header: :headers '("\\usetikzlibrary{calc,positioning,patterns}")
| #+begin_src latex
| \begin{tikzpicture}[on grid,
|   font=\footnotesize,
|   level distance=2.5cm,
|   sibling distance=2.5cm,
|   every node/.style={circle,draw,fill=white},
|   touch/.style={circle,draw=red!100,fill=red!40,thick},
|   invirtueof/.style={circle,draw=red!50,fill=red!20,very thick}]
|
|   \node [invirtueof] {Car}
|   child {node {wheel}}
|   child {node [invirtueof] {body}
|     child {node {driver door}}
|     child {node [invirtueof] {passenger door}
|       child {node [touch] {region of door}}}};
| \end{tikzpicture}
`----

This works almost perfectly. It's set generate an EXPORT block of LaTeX
code when exporting, and an inline image in the results block otherwise.
When generating this inline image, it takes into account the necessary
`:packages' and extra `:headers' defined.

The only problem is that when I export to LaTeX, what is included is
/just/ what was in the results block, which is /just/ the code inside
the original src block (i.e. the export does not include the `:packages'
or `:headers' information, and thus fails to compile because the LaTeX
file doesn't load tikz).

Is there a way around this? Either to export the src block another way,
or to add metadata to the to the resulting EXPORT block (or just text,
though I'm not sure how that would work for `:packages', since they
require text to be added to the resulting exported LaTeX file in a
different place from where the text of the block goes).

Ideally, I would like to not have to change anything in the file between
working on it (previewing) and exporting. Solutions to similar problems
(e.g. <https://emacs.stackexchange.com/a/60714/34394>) seem to require
commenting and uncommenting lines. I would really like a single,
write-once solution (and am perfectly happy with it being verbose).

If there /isn't/ a way to do this at the moment but someone knows
roughly what would have to change in org for there to be, that would be
great information to have too. I would be happy to try to work up a
patch. I've looked at some of the code and it looks just about
approachable.

TIA

Hugo