The "finished set" is a term that Cantor introduced to
distinguish arbitrary totalities from the inconsistent
multiplicities that could not be formed.
The real issue with Cantor's work would seem to be the
relationship of logic to mathematics. For example,
Kant makes a statement along the lines of the
paraphrase "the singular judgement is to the universal
judgement as an individual is to infinity". In this
construal, infinity arises by addressing the nature
of "universes of discourse" as criticism of mathematics
leads to logical solutions.
Of course, this is not so apparent in Cantor's work as
it would be if used to describe Frege and Russell. But,
with Dedekind and Cantor, the issue of developing an
arithmetical continuum had involved the nature
of "systems".
The nature of identity with respect to the received
paradigm arises from logical atomism and reflects on
the matter in terms of "self-identity", an ontological
necessity. However, identity with respect to a system
involves "identity and difference" (Heidegger's title).
My book in relation algebras attributes the observation
that every system has 4 necessary relations:
The total relation consists of all ordered pairs.
The empty relation consists of no ordered pairs.
The identity relation consists of ordered pairs
whose relata are co-referring names.
The diversity relation consists of ordered pairs
whose relata are never co-referring names.
The identity and diversity relations are logical
complements. So, in relation to systems one has
"identity", "negation", and "totality" intermingled
before one ever states that about which one is
speaking.
Brouwer, thinking of the classical syllogistic
hierarchy, introduced the notion of a pre-linguistic
mathematician precisely because he saw the "part"
relation of syllogistic logic as imposing itself
upon mathematics in foundational pursuits. But, he
overlooks the fact that the continuum can be perceived
as a system of co-extensive parts (Leibniz makes that
exact statement, for one). One of the things that
distinguishes the modern logic from the classical
Aristotelian forms is that it can refer to parts of
objects as individuals. So while there are phiosophical
differences between Cantor's "finished classes" and
Frege's "extensions of concepts", there had been
a convergence among lines of reasoning leading up
to the situation in the foundations of mathematics.
It is a shame that the only reason you seem to have
done your researches had been to discredit the notion
of infinity as it is used in mathematics. Had you
not pursued these histories with an agenda, you may
have had a greater appreciation for how modern
mathematics came to have the form that it does.