Okay, about titles.
First of all, ignore the NoA titles completely. Let's use the original japanese titles.
Japanese fiction really likes to use the title of Maō to the main antagonist, which has been translated several times as "Demon King" or "Devil".
Daimaō means "Big Maō" or "Great Maō", and is often translated as "Great Demon King".
Yami no Maō means "Maō of Darkness" or "Demon King of Darkness".
In the Zelda series, the titles used are teh following:
Maō - OoT and TP
Daimaō - LoZ, AoL, OoX and TWW
Yami no Maō - OoX, LttP and FSA
Back in the days when theorizing in ZU was done only by a small group of theorists, this was a very recurring topic that was discussed. Basically, a group of theorists that defended what I like to call Leximgard-Skyral theory, argued that games showing the same title should come together in the timeline, OoX serving as point in which the title changed (it was the only game to show both titles).
This is what they believed:
...../-TWW---LoZ/AoL-OoX---FSA-LttP/LA
OoT
Blue being Daimaō Ganon arch, purpleish being the changing point for titles, and red being Yami no Maō Ganon arch.
Anyway, a better annalysis is definitely needed here. First of all, what exactly is a Maō? Well, I am no expert in Japanese culture, but, from what I got in ZL, a Maō is a class of demon is japanese fiction that controls a specific territory. So, it is a generic title, meaning there can be different maōs in the same universe, as long as they control different territories.
This is already good enough to show that Malladus having the title of "Demon King" (Maō) in ST isn't really a problem.
Daimaō, in my opinion, is also a very generic title. It is a Maō (or Demon King) that is more powerfull: "Great Demon King".
Now, on the main subject of this thread, I believe the only title that is important to the timeline is Yami no Maō. In FSA, they make it quite clear that, in order for one to become the Yami no Maō, he has to claim the trident of power. So, it is a very specific title, awarded only to the bearer of the Trident of Power.
Talking about "Maō", "Daimaō" and "Yami no Maō" is like talking about the titles of "King", "High King" and "King of England". When I say King, I am referring to any king. It is a generic title, pretty much like Maō. When I say High King, on the other hand, I'm still referring to a generic High King (for example, the High King of Ireland), but is more powerfull than other kings (the other kings in Ireland). It's just like differing from "Maō" to "Great Maō" (Daimaō).
Now, when I say the "King of England", I'm referring to a very specific king. The one who reigns over England. Similarly, when I say "Maō of Darkness" (Yami no Maō), I'm referring to a very, very specific Maō: the one who owns the Trident of Power. Because of that, I believe the only title that shows any importance to the storyline is that of Yami no Maō.
By that logics, it is wise to assume that all games showing Ganon holding a trident are supposed to come after FSA in the timeline (this is, most probably, what the devs intended with the whole trident backstory in FSA). So, LttP and OoX would have to follow FSA in the timeline, so we would have:
Yami no Maō Ganon being born in FSA;
Yami no Maō Ganon being killed in LttP;
Yami no Maō Ganon being ressurected and killed again in OoX.
So, imo, the order should definitely go as: FSA-LttP/LA-OoX