I had this little bit bumping around so here it is, the AU where Jack is welcome on Nemesis and Soundwave has hobbies.

Nemesis was no place for humans, human children even less so, but Jack had somehow ended up in their graces to be allowed not only on board but to roam freely in their midst.
This did not mean that he was safe from accidents.
-"T - there is a tiger!" Jack sprinted down the corridor, skidding slightly as he took a sharp turn to barrage into med-bay.
Breakdown turned to face him with calm demeanor that contrasted painfully with Jack's agitation -" A what?"
-" A big cat! A big cat that eats animals. Like humans !" Jack waved his hands around himself in circular motion trying to emphasize the 'Big' part of his argument.
-" Where?" A sleepy-lazy question sounded somewhere from behind Breakdown. Apparently Jack had interrupted something intimate but neither bot seemed to show any discomfort about that.
-" I, uh, sorry, I can wait outside until…" Jack stammered when Breakdown stepped back and Knock Out was raising himself from the berth. The red mech cut Jack off with a motion of servo. -"Where again?"
-" Soundwave's room?"
There was a meaningful pause where each occupant of the room looked at each-other.
-"What?" This time it was Knock Out's turn to ask.
-"Why were you even there?" Breakdown supplemented. -"You know Soundwave likes privacy right?"
Knock Out rubbed his nose-bridge. -"Let me handle this." He tapped the side of his head for a comm. -"First North-American condors, now this..." Knock Out muttered to himself as he headed towards Soundwave's quarters.
Jack settled in half-jog next to Knock Out as they walked through the halls -"The what? I did not know you had such good knowledge of terrestrial animals."

-"I did not, until now" Knock Out grumbled

-"But why?"

-" It reminds him of his minicons."
At Jack's lack of understanding he added, -"Bots that were part of Soundwave's, uh, pack, like Laserbeak? In this case it is about Ravage." Knock Out did not have time to delve into the fine details of how mechs like Soundwave functioned and what it meant to be like him but he hoped that the rough generalization conveyed enough meaning to Jack at this moment. He made a mental note to elaborate on it later. -"Ravage was sent offline halfway through the war and it did resemble the 'Tiger' you mentioned before."
-"Oh… But they are endangered, you know?"
-"Huh?"
-"Like in danger of going extinct?"
-"Why?"
-"Poaching."
That gave Knock Out an idea, his lip plates quirked into a small grin -"Well, maybe that will give Soundwave a new little Earthen project to work on then."
-"What?"
-"I'm sure he will enjoy it."
Jack rubbed his head frowning -"You mean Soundwave against poachers to protect tigers?"
-"Would you put it past him?" Knock Out smirked and knocked on Soundwave's door, it slid open.
-"Just unusu.. Argh!" Jack leapt up in alarm and scrambled up Knock Out's leg.
Knock Out whistled at the sight before him. For a lack of better word there was a literal habitat in Soundwav's room. Soft padding with real tree logs scattered about, a running water fountain which more likely than not had been uprooted from somewhere and a bunch of orange and black-striped felines lounging around in different areas.-"You did not say there were more than one."
-"I did not exactly stay long enough to count them."
Knock Out put out his servo so that Jack could clamber on top of it and out of the harm's way. In the back of the room Soundwave was letting one of the large felines climb up the flat of his arm, leaving shallow scratches in its wake. The TIC seemed content.
Knock Out sighed, curse the war. -"Soundwave, we need to chat."

This was fun. Might add more at a later date