I’m just imagining the squad slowly forming based on the benders Varlen needs to learn from…

He’d start off being found by Darren and Lyrene, with Darren acting as his waterbending teacher. But, of course, Darren’s not great at it, so it’s more the two of them fumbling about trying to make it work. Varlen picks up a few things, but quickly outpaces Darren’s ability, forcing them to head off and attempt to find more skilled teachers. 

After failing to find any waterbending teachers, they’d shift tact and head over to the Earth Kingdom. There, they would stumble across Hanin, a displaced former soldier who’s village had been attacked by the Fire Nation and reduced to ash. They join him on his journey to Ba Sing Se, all the while keeping their respective bending abilities a secret from each other; Hanin not wanting to reveal that he is more than just a soldier to strangers, and Varlen obviously trying to keep the fact he’s the Avatar on the down-low because of the Fire Nation presence in the area. However, they are waylaid on their way to Ba Sing Se by a group of Fire Nation soldiers and forced to use everything at their disposal to get away. Varlen uses airbending to try to protect everyone but is injured in the fight, and Hanin ends up pledging his loyalty to the Avatar after defending him and revealing he is a skilled earthbender. 

After an eventful trip to Ba Sing Se, they come across a group of prisoners being escorted by members of the Fire Nation army. Varlen decides he wants to free them despite Hanin warning him against it due to his still-healing injuries. They attack and everyone but Lyrene ends up getting captured. She follows from a distance, harassing the group and convincing the Fire Nation soldiers that the forest they are travelling through disapproves of their capturing of the Avatar and is turning against them through creative use of archery, traps, and mind-games. One of the captured Earth Kingdom women happens to see her on the second day, but keeps her mouth shut, instead subtly directing their captors towards Lyrene’s traps and assorted shenanigans. The woman’s name ends up being Leah Connors, another earthbender. She joins the group and assists Hanin in training Avatar Varlen due to his extreme difficulty picking up earthbending. It is an ongoing process.

As they continue travelling to the outskirts of the Earth Kingdom, news of the Avatar’s presence spreads like wildfire. Varlen and the group find themselves constantly having to watch their backs, pursued doggedly by a disgraced Fire Nation General called Joustis. However, when they eventually end up cornered, Varlen gives himself up as a prisoner in exchange for letting the rest of his friends go. He was taken to a stronghold on the west coast of the Earth Kingdom that had been taken over by the Fire Nation, but was eventually freed by two very unlikely people; a non-bender named Ralon and a firebender named Cyrus. The two bickered through the entire process, but they actually ended up working quite well together when push came to shove, combining Ralon’s cunning with Cyrus’ knowledge of how the General operated to sneak Varlen out of the stronghold. They managed to slip away into the nearby forest where they met up with the rest of the Avatar’s group, clearly in the middle of planning a rescue mission. They abandon it with relish and flee north.

Avatar Varlen starts learning firebending from Cyrus, and although Cyrus is a very impatient teacher, he picks it up a bit better than earthbending. Hanin goes through a bit of an emotional breakdown, convinced he has failed to do his duty and teach the Avatar, and therefore failed everyone relying on the Avatar to confront the Fire Lord with the mastery of all four elements on his side. Cyrus gets into a tonne of arguments with everyone over where his loyalty truly lies, and it is eventually revealed that he is the son of General Joustis, which paints an even bigger target on all their backs as the General assumed his son had been kidnapped as a personal insult. They eventually head to the Northern Water Tribes to seek out a waterbending master for both Darren and Varlen, where they engage in a dramatic battle with General Joustis’ fleet. 

Anyway… that’s all I’ve got so far. I can barely remember what happened in ATLA because it was so long ago, but that’s the gist of it for now haha