(a) The point on the yafutei shel yefet in your insights on the daf still seems to imply that the greek alphabet is more beautiful than the hebrew. What about v'rommantanu mikol lashon etc." Also would you say that the concept of using the greek beauty in its proper way (within the bet mikdash) implies that there are items in non-Jewish culture which may have some value? Is this generally accepted in orthodox Jewry?
(b) Do you see R'Yishmael as arguing on tanna kamma, explaining, or talking about a different time period?
(a) The "beauty of Yefes" refers not to the Greek language in general, but to the script and the letters which are used. The Greek letters are indeed considered to be beautiful, more so than the Hebrew letters. However, the Hebrew language is certainly more holy and contains much deeper significance than any other language.
In all other languages, a word is merely an arbitrary assignment of reference to an object or concept, but the word itself does not contain intrinsic meaning with regard to that thing. In Hebrew, the word itself has essential meaning with regard to the object it represents (for example, the word "dog" in English is an arbitary assignment of phonemes to designate an animal that barks and has four legs; in Hebrew, the word "Kelev" comes from the contraction of the words, "Kol Lev" -- a dog is "all heart" for it is very friendly and "is man's best friend").
Yes, there certainly are items in non-Jewish culture which have value, as we find in Maseches Shekalim as well (14a). Generally, any item which can be used to further the awareness of the glory of G-d in this world is valued. (See also Midrash Rabah Eichah 2:13 "If you are told that there is wisdom among the nations, believe it." Rambam writes in his Introduction to the Mishnah tremendous things about Aristotle's understanding of philosophy and the metaphysical).
(b) We learned the Mishnah according to the explanation of the RAMBAM, who implies that they argue (Hilchos Shekalim 2:7). The ME'IRI also understands them to be arguing.
However, RABEINU MESHULAM and others question this explanation and ask that if they are indeed arguing, what is the basis of their argument. They do not give an alternate explanation, though.
HaRav Chaim Kanievsky (in Shekel ha'Kodesh, Tzion ha'Halachah 118) answers what the argument is, based on what is written in the Teshuvos of the Rambam. The Rambam writes that a Get, divorce document, is written in Aramaic because it is not proper to write such a document in Hebrew, which should only be used for Divrei Torah. Thus, the Tana Kama in the Mishnah maintains that the letters written on the Kupos is considered Divrei Torah, and therefore they are written in Hebrew, while Rebbi Yishmael argues and says that they are not considered Divrei Torah, and thus they are written in Aramaic.