I have put together an episode of Lifetane (Japanese version here). I will update it as needed. Please note that there may be omissions or mistakes.
The English is strange because it was written by a Japanese who is not good at English.
Thanks to all of you who helped me scrutinize the information!

●Episodes (in chronological order)

1) When Octane's pet rabbit (Navi) dies, Octane and Lifeline conducted the funeral.

Source: season 12 battle pass wallpaper "Eulogy for Navidad 'Navi' Silva"

2) At the age of 19, Octane and Lifeline ran away from their home planet (Psammate).

Source: Pathfinder's Quest

3) Lifeline joined the band and then the Frontier Corps. When the medicines of the Corps were about to run out, Lifeline asked Octane for help. Octane was overjoyed and rushed over to help her steal medicine from his father's company.

Source: Outlines Stories, "Family Business."

4) Octane exploded his own leg in the gauntlet. Lifeline arranged a prosthetic limb for Octane.

Source: Octane character introduction page

5) In order to rescue Octane, Lifeline interrogated a civilian woman (who was dating Octane) who held information.

Source: season 5 story

Tip: Later, Lifeline, angry at Octane for being reckless, blocked Octane. Octane barged into her home and they maked up.
Source: Web comics

6) During a live performance, Lifeline was injured by an attack. Octane ran 10 miles with her in his arms to take her to the hospital. (*Time line unknown)

Source: Overtime

7) In order to obtain old Marvin's battery, Lifeline attended a charity party and attempted to contact her father who was attending the party. An attack occured at that party, but Octane, who followed her, succeeded in becoming Lifeline's bodyguard.

Source: Season 7 story "Family Portrait"

8) Octane learned that Octane's father (Duardo) was the main culprit behind the (7) attacked and the pandemic caused by Icarus. Octane carrieed out a cover-up to erase his father's name from Icarus. Meanwhile, he questioned his father about the attack. But his father attacked his character, which caused him to cry and beat him. Then Lifeline appeared and confronted Duardo with the Peacekeeper.

Source: Web comics

9) Octane and Lifeline tryed to stop Octane's father's plot. In their search for the truth, they discovered that Octane's real father was already dead. However, Octane found evidence that Duardo might love him and be trying to change his mind, and suggested that he should remaine quiet. He was at odds with Lifeline, who wanted to stop Duarte's plan, and they fought when Octane burned the death certificate, which was proof that the real Duarte was dead.

Source: season 12 episode "The Perfect Son"

10) Lifeline joined forces with Maggie to defeat Duardo. Octane doesn't like their relationship and was jealous.

Source: Season 16 Battle Pass Reward Level 13

11) The Legends attend a party at Duardo's home. Lifeline teamed up with Crypto to hack Duardo's PC. However, Duardo almost catched her in the act. However, because Octane spoke to Duardo just before the crime, Lifeline was able to avoid detection.

Source: Web Comics