Here I am. I am responding between the lines by changing my text color, not out of a desire for protagonism, but because it is more convenient.
I will proceed in order.
So, let's take stock because the issue has become a bit scattered.
Summary of what I have understood and some doubts from the first half:
Sonata form
EXPOSITION - First theme: from 1 to 8 -
Transition: from 9 to 12 -
I would note that these four measures are used by Mozart as a liquidation at the end of the 1st movement (m. 201 onwards).
He does this, albeit in a different way, also in Symphony K 550 in G minor, where he uses the main motif (Eb Re Re etc.) as a cadence at the end of the development to introduce the recapitulation.
First theme: from 13 to 18 -
Development I theme: from 19 to 22 -
In my opinion, it is too "Flemish" to divide measures 13 to 22 as you have done. It simply seems to me that, apart from the first 8 measures (1-8), from 1 to 22 we are in the «first theme region» which has the logical consequence of moving towards the dominant. That is what actually happens here.
Dominant pedal: from 23 to 27 -
Modulating bridge in the key of the dominant: from 28 to 32 -
I have a mania for simplifying, but, strictly speaking (perhaps I am saying something silly), does it make sense to have a «modulating bridge» after one has already arrived at the dominant? In my opinion, from 23 to 37 we are simply in the presence of a transition section whose purpose is to confirm the key of the dominant to prepare for the entry of the 2nd theme. As usual, I will perform a check (the litmus test): let's eliminate all measures from 23 to 31 and try to play by joining 22 to 32. Does it work? Yes: it is ugly, but it works, because at 22 Mozart has already arrived at the dominant and only needs those ten measures to reinforce that harmony.
Second theme: from 33 to 40 -
Development second theme: from 41 to 76 (tonic pedal from 41 to 44)
Therefore, a two-theme exposition with a ritornello that touches the tonic and dominant areas respectively with the first and second themes.
The last two measures of the exposition, in particular the last one, are: - speaking of the ritornello, a V7 of A+ - speaking of the development, a V7/V of D+, beginning of the development.
Second theme region: from 33 to 51. The actual second theme, if we want to be extremely strict, ends at 44 (and if we really want to be as nitpicky as possible, measures 41 to 44 could almost be considered a new thematic element, but that would be a real stretch, even if...)
From 45 to 51 there is another short conjunction section which once again has the function of reconfirming the key.
At 52/53 (the measure with the viola repetitions is outside the count for me: I consider it a neutral measure) the coda of the exposition begins.
A look at measures 59-62: what do you see? Exactly: that thematic element we found at 41-44, only slightly enriched and modified (the trill and the two ascending repeated notes, instead of descending).
DEVELOPMENT: to be looked at in detail but from measure 77 to 107
RECAPITULATION: to be looked at in detail but from measure 108 to 184 CODA: from 185 to 205 (end)
Therefore, doubts:
HARMONY Exposition measures between 63 and 66.
None of the examined solutions convince me 100%.
I am sorry to Oracolo and Marzapane, whom I thank for their availability. I like the idea of the progression, but the scheme is not yet clear to me.
I haven't read the other solutions, so I might repeat things already said, but I would say it like this (attention: I am putting the degrees reasoning in E major!):
m. 63 I6 (the chromatic movement of the violins has no harmonic function),
m. 64 IV - #II7
m. 65 I6 - #I seems to be a tonicization of II, so it could be read as #VII of F#, but it is not, because the oboe holds the B, so:
m. 66 V36-V56 then, a very normal cadence:
m. 67 I - VI
m. 68 V - I
FORM The development and the recapitulation are in a ritornello, at the level of sonata form; what does this entail?
Nothing: even in this case Mozart uses some measures (179-184) to bring the discourse back to the development, but the Symphony could have ended as follows, i.e., by cutting everything from 179 to 204. It works the same way even without a coda, a coda which, at this point, results in being insignificant for the balance of the «sonata form» (I don't mean to say he shouldn't have put it: the question was precise, the answer is drastic, but it only refers to a formal discourse).
Thanks to anyone who wishes to provide further input.