This is how I think the timeline might look with the additional information from the Lion Guard for my stories. Enjoy
Some time ago: the second born of the first king established the lion guard and that king found the first bunch of Elelphant Graveyards
Years before Scar's time: Dark lions such as Samira and Aibu did terrible things to the pridelands
about 30 something years ago: Mufasa is born followed by Scar to Ahadi and Uru
6 years later: Mufasa is betrothed to Sarabi, Sarafina is bethrothed to Nyekundu, Nala's future father.
2 years later: Scar gets his scar and leads his new lion guard as a teen (See 'Taka's Guard' for details)
4 years pass: Scar destroys his guard after they don't help him kill Mufasa and goes to the hyenas to slowly plot his revenge
a year after: Muafasa and Sarabi are married.
3 years pass: The start of LK 1 1/2 with Timon's origin
4 years later: The start of the lion king occurs: Simba and Nala are born roughly at the same time (Behind the scenes, Nala's dad leaves the pride)
3 years later: Simba is old enough to talk and the first half of the movie when Simba and Nala are cubs occure (The scenes that explain important scenes like te animals falling over at the end of 'Can't wait to be king' overlap)
About 2 months before Simba's return: Kovu was born and chossen as Scar's heir with Nuka, Vitani and Zira as witnesses
4 years later: Simba becomes a young adult and the second half of the first movie occurs
3 months pass just before the end (So before the animals return to Pride rock): Zira and her lionesses return from an unsucessful hunt to find Scar dead. Zira attacks Simba but Simba defeats her and banishes them all to the outlands.
The surviving Hyenas escaped from the Pridelands for unknown reasons had cubs in the outlands.
The end of lion king 1 1/2 (Minus the cinema part) Happens
2 months pass: The end of the lion king and Kopa is born.
Kopa's adventures from SNA occur over 2-ish years
The following year: the start of the lion king 2 occurs and Kiara is born. Kopa runs away as Kiara is presented to the kingdom and reunites with Asante in the jungle
4 years pass: The first half of LK 2 happens when Kiara is able to talk and meets Kovu
2 months after: Kion is born.
Around this time, Bunga is born to his unknown parents.
4 weeks later: The flashback seen in the song 'The Path of Honor happens
Once Bunga is about 3 weeks old and able to walk, he's abandoned and runs into Timon and Pumbaa singing the 'Utamu' song
1 year 5 months later: Kion meets Bunga, Fuli, Besthe and Ono seperately on different days for the first time
Over a period of about 4 years: The events of the lion guard and the events of 'The Dark Roar rises' occur
Some time before Kion meet Kovu, Vitani, Nuka, Zira and the outsiders: Kion and his friends do meet Kopa and Asante but Scar uses one of his abilities make them forget that adventure
At the end of the fourth year: Kion and his friends have to leave the pridelands to find other animals to help while Makini goes on a knowledge journery
Over the following year: The Second half of the LK2 occurs
Kion returns to the pridelands before Zira declares war on Simba's pride and attacks Kopa just after Zira died and the outsiders sided with Simba's lionesses.
Kion is then exiled and is never seen again for a long time.
The other lion guard members return
2 months later: Kiara and Kovu get married.
The lion guard is soon disbanded
the events of 'The Dark Roar returns' occurs
Note: More will be added as time goes on