My question is in the title. Some context: there are two versions of the O'Nan-Scott theorem. The first, weaker version, is due to O'Nan and Scott (independently) and gives the structure of the maximal subgroups of a finite symmetric group:

A maximal subgroup of $S_n$ is one of:

$S_k\times S_{n-k}$, the stabiliser of a $k$-set (that is, intransitive),

$S_a \mathrm{wr} S_b$ with $n=ab$, the stabiliser of a partition into b parts of size a (that is, imprimitive), or

primitive (that is, preserves no nontrivial partition) and of one of the following types:

$\mathrm{AGL}(d,p)$ with $n=p^d$,

$S_\ell \mathrm{wr} S_k$ with $n=\ell^k$, the stabiliser of a product structure,,

a group of diagonal type, or

an almost simple group.

**Question 1**: Am I right in thinking that this theorem does not depend on the Classification of Finite Simple Groups (CSFG)?

(Note, of course, that you need CFSG if you want to explicitly list the almost simple groups at (4). But such an explicit list is not a part of the stated theorem.)

The second, stronger, version of the O'Nan-Scott theorem is due to Aschbacher, O'Nan and Scott, and gives the structure of all finite primitive permutation groups. I'll state an abbreviated version.

A primitive subgroup of $S_n$ is of affine type, of wreath type in a product action, of diagonal type, of twisted wreath type, or almost simple.

All the proofs of this result that I have seen depend on the Schreier Conjecture, which asserts that the outer automorphism group of a finite simple group is solvable. This Conjecture is known to be true but only as a consequence of CFSG. So....

**Question 2**: Is it true that all known proofs of the Aschbacher-O'Nan-Scott theorem depend on CFSG?