Thank you for answering about Sharess and Shar.
One final question about them: is the similarity of their names just a coincidence?

And this is your problem. Planescape deities aren't people. They are forces of (super-) nature that occassionally look like people. They can be in many places at once. They can form avatars and aspects. A deity can sense things miles away, hear every instance of their name spoken by a mortal, notice every event involving their portfolio in their area of worship, sometimes weeks before it happens. A deity's personality is formed by their portfolio and the beliefs of their worshippers.
A deity is not a person. It's a power.
Okay, I can accept this. The quote reminded me something from Norse mythology. This religion is old gone, but still a religion, so I don't know if it can be discussed. Probably not.

But I do want to explain why I said that deities in this cosmology are people.

Remember Avatars series? Yes, in three original books deities looked and behaved as people because Ao forced them to this. But the fourth book (different author I think) describes them already after this. And why I say that they behave as people, though their alignments are extreme.

Midnight\new Mystra still loved Kelemvor, but suspected he now sees her physical form as a mummy. Cyric was cheating and plotting as he did in life. It took gods so much of effort and time to reclaim Cyrinishad, and then Mask stole it again, just for lulz. He also said, leave me alone, stealing is my nature. Kelemvor even tried to continue being honest judge of souls, and started sending souls to the Wall only after being scolded by Ao. And it was Cyric who snitched on Kelemvor to Ao about this.

Even in the first book, Helm, the only one who wasn't made mortal, in the scene when he killed old Mystra, while he really created a few forms of himself, he still had a humanoid form and talked like a usual devoted warrior.
Those series do describe deities as people, and they do behave as people.
Are they considered canon or not?