Is that it?
Yes. I think an argument can be made that the Baklunish don’t import the deities of other pantheons into their own worship. The first is historical; if one looks at the map of the migrations of various races across the Flanaess (on p. 10 of the Guide), the Baklunish made naught but a half-hearted foray into the lands currently occupied by the nomads. The proximity of the Oeridians to the Baklunish heartland explains how the Oeridians could have taken the worship of Geshtai and Xan Yae into other lands, as they spread their own vibrant culture and most of their own pantheon. Yet no other cultures made any inroads anywhere close to the Baklunish lands. They are outsiders; aloof, and they are often portrayed as exotic strangers in some of the fiction that takes place in the Flanaess.
It should be noted, too, that Istus, for all her prominence in the setting (including having a rather large, if uneven, module named after her), is not listed as a “common” deity. She is also the only Greater God in the Baklunish pantheon (not that there are all that many Baklunish gods to choose from…). We are told that her centers of worship are Greyhawk (which boasts a small, if identifiable, native population of Baklunish extraction– notably the only land in the Flanaess that does), Dyvers, Rauxes, Rel Mord, and Stoink. All centers of trade. It is not unreasonable to conclude that those “centers of worship” are merely for the benefit of the Baklunish traders who frequent those capitals of commerce (Stoink, we are told, is a “wasp’s nest” of illegal activity, so those Bakluni indulging in the commerce of contraband might well have something of an outpost within its walls).
There is also the commentary of Gary Gygax himself on the subject:
The plan was to introduce a new pantheon of [Baklunish] deities. Obviously that never eventuated… nor will it ever unless WotC decides to do so.
EGG’s (understandable) bitterness aside, it speaks to the notion that the Baklunish gods were only partially represented in the World of Greyhawk boxed set, and that their expansion was eventually supposed to have happened. To me, that reinforces the surmise that they are not included in the “common” designation for the other deities. Bear in mind, too, that a natural definition of the Flanaess would begin, not at the left-edge of the Darlene map, but rather at the line of mountains beginning at the Hellfurnaces, through the Crystalmists and Barrier Peaks, and up to the Yatils (much like the Ural mountains are said to divide Europe from Asia).
That being said, and operating on the assumption that the Baklunish haven’t imported any gods from the other cultures of the Flanaess, but rather only loaned out two of their own, whose worship was disseminated through the auspices of the Oeridians, several conclusions can be made.
They tend towards neutrality, and they tend towards female deities. The lawful neutral alignments designated for Zeif and Tusmit, as well as the neutral good alignment of Ekbir support this notion obliquely, although I would daresay that a fully-developed Baklunish pantheon would display the same characteristics of the other pantheons thusfar found in Oerth; a marked tendency towards neutrality on both axes, but with certain deities of more defined alignments being presented related to specific interests.
Coming up next– wrapping it all up, and presenting some conclusions about the nature of religion in the Flanaess.