Why does the phrase "Religion is for Allah" appear in the verse from Surat Al-Baqarah, and "All of religion is for Allah" in the verse from Surat Al-Anfal?

The difference between "and [that] the religion will be for Allah" and "and [that] the religion will all be for Allah" lies in the context of the two verses. The verse in Surah Al-Baqarah speaks only about fighting the polytheists of Quraysh, among whom there was no religion other than their own, hence the omission of the word "all" was appropriate. As for the verse in Surah Al-Anfal, it came in the context of discussing fighting disbelievers in general, among whom there might be followers of different religions. Thus, the mention of the word "all" was appropriate to indicate that Islam prevails over all religions.