In FR the dragons were created by the primordials. Does this mean many/most/all dragon gods are also primordials, as aspects/fragments of Io?
The Dragon Gods are presented as actual gods rather than primordials (DMG p. 10, PHB p. 296, & SCAG p. 113).
Can a primordial also be (or somehow become) a god?
I'm unaware of this occurring, but I wouldn't rule it out:
- Asgorath/Io is both, but (as creator of the universe) doesn't count.
- Tharizdun is close, but is not a Primordial.
- Kossuth is also close, but he's "not a true god but actually an
elemental primordial".
Do primordials need, desire or benefit from followers?
Not normally, but Kossuth is an example of a primordial that benefits from extensive worship.
Do surviving primordials have significant religions associated with them, either in Abeir or in Toril?
On Toril the five Elemental Lords have followings, while The Seven Lost Gods were once worshiped. I believe Abeir would have more significant Primodial worship, but that setting was never detailed.
Do primordials grant spells in the same way as gods?
Not normally, but again: Kossuth is an example of a primordial that both grants spells and has extensive followings.
Can they be warlock patrons?
I don't see anything preventing this. A few homebrewed examples of this can be found here and here.
Is there any obvious difference in the portfolios of primordials versus gods? I would have assumed that since they predate mortals they tend to represent more fundamental forces (like the elements) rather than human concepts like law, love, luck, agriculture.
That might be one way to view it, but 4e's creation myth (Worlds and Monsters p.56, cited below) has the Gods being created at the same time as the Primordials. Another way to view it might be that the Primordials are composed of elemental "physical-matter" while the Gods (and Astral Sea) are more composed of thought (mental-matter).
In short, what is the difference between a god and a primordial? Are they fundamentally the same (just different lineages) or are there fundamental differences?
They are consistently presented as having fundamental differences. From 4e's Worlds and Monsters (p.56): "The gods, beings of divine power, appeared in the Astral Sea, while in the Elemental Chaos arose the primordials, incarnations of tremendous elemental might"... "composed partially of creation-stuff".
I also found this fantastically detailed post on Candlekeep...
That still seems like as good a guide as any.
Yes, and the type of society varies.
MM 207 describes the various types of communities that lycanthropes inhabit. Many are solitary, but wereboars, wererats, and werewolves sometimes form societies.
Wereboars:
Wereboars live in small family groups in remote forest areas, building ramshackle huts or dwelling in caves. They are suspicious of strangers but sometimes ally themselves with orcs.
Wererats:
Wererat clans are found throughout urban civilization, often dwelling in cellars and catacombs. These creatures are common in the sewers beneath major cities, viewing those subterranean areas as their hunting grounds.
Werewolves:
In the wild, werewolves form packs that also include wolves and dire wolves.
Judging from these, it's mainly the evil lycanthropes that form societies.
Best Answer
If it can understand morality enough to have an alignment, it can worship whatever deity it chooses to
This is a bit of a strange situation; in comments, you mention how its stats are as per the Monster Manual, so an Intelligence score of 3, but it is also Lawful Good.
RAW, generally beasts with an Intelligence of 3 or less are unaligned, which makes sense because they wouldn't be smart enough to understand morality. It also makes sense to me that they wouldn't be able to comprehend gods either, so dogs wouldn't worship anything.
It sounds like you have misunderstood alignment here, which are to do with morals and principles, I'm not sure that "pack animal instincts" can be thought of as "Lawful Good". The dog isn't moral because people call it a "good dog", and obeying their "master" isn't lawful as that's just their pack mentality, not a choice the dog is making based on its "principles".
However, if, despite that, you decide that this dog is somehow Lawful Good, this implies that, despite its low intelligence, it can grasp the concept of morality, so if you rule that it also understands gods, then at the very least, this dog may worship whatever god you feel makes sense for that character.