What is your belief to why Remus does not reach out to Harry, in particular when he was younger? I personally believe it's due to his own inferiority complex and legal laws.
I believe you might be right. Here’s some thoughts on the matter:
1. Remus lost everything in the war. I think it’s safe to say that Remus was caught up in his own grief for a long, long time. There would have been a recovery process that wasn’t at all what a recovery process should be, and at the end of which I think Remus would actually have felt guilty for not contacting Harry for all those years and sort of let him just… be. Harry was just an infant when he was lost, so to speak. What would Remus even say to him now, years later? “Hey, I knew your dead parents! Hope you don’t, like, miss them or anything.”
2. Remus was a part of the world that Harry was deliberately left out of for his own safety and sanity. Remus is a wizard. Remus is a werewolf. And even if Dumbledore allowed outside contact (which it does not appear that he did, because no one contacted Harry, not even strangers who would have adored the chance to dote upon smol baby Harry with the newest and shiniest Wizarding baby toys), Remus seems to not really be aware of where Harry actually lives. I wonder if it’s even possible to send an owl that way. I think this is Dumbledore’s doing, because like I said, no one sends Harry anything, and for being The Boy Who Lived–a celebrity–Harry would have gotten a lot of weird things, like celebrities are wont. I think his location was definitely kept a secret for his own safety from Death Eaters and crazed fans in order to give him the chance at a normal life.
3. Suppose that Remus does in fact know where Harry is. He would have to get through Petunia and Vernon first, which honestly sounds harder than thirty consecutive days of werewolf transformations. They literally went to a remote island during a damned hurricane to stop Harry receiving mail, even after the mail poured in from every crack and crevice in the Dursley home. The Dursleys were pretty seriously determined to keep Harry away from any of the Funny Business as possible, and not only is Remus an ex friend of one horrible man named James Fleamont Potter, but he also looks ill all the time, like he’s carrying some sort of unfortunate disease that they don’t want to be anywhere near. Not to mention the fact that he may be kind of… homeless. Remus isn’t really a character the Dursleys would have even humored approaching their doorstep or sending secret letters to their not-a-son.
4. And more on the support for the “Remus had no idea where Harry was” theory, Remus doesn’t talk about the Dursleys, ever. He doesn’t talk about the abuse Harry has undoubtedly suffered, or the fact that he clearly would have seen Harry put on some weight after getting back into the healthy environment of Hogwarts where he gets three square meals and only beaten up at the end of the school year by Voldemort instead of on a daily basis by Dudley. I think he knows by OotP, especially when Harry quips about the Dursleys not missing him and Remus cracks a little half smile. But to be honest, at that point I think he’s firmly under the “this is what Dumbledore believes is best, and I trust Dumbledore” mentality rather than, “Oh my god, look at Harry, he’s so skinny and his clothes are clearly giant hand-me-downs.” It’s questionable how much he actually knows about just what Harry’s had to face at home. Because I think if he did know as a younger man, he would have pitched a fit to Dumbledore about it because he loved Harry like a nephew. A decade later, Remus is an older, wiser man and able to step back, listen to Dumbledore’s warning about what is necessary, and control his horror at what he’s seeing.
Since I saw your Toshi and Deku Treasure Planet comic, I cannot stop thinking about Uraraka and Bakugou in the Dr. Doppler and Captain Amelia scene - Ba: "We must stay together and- (groans)" Ur: "And what? What? We must stay together and what?!" Ba: "Uraraka... you have wonderful eyes..." Ur: "Deku, he's lost his mind!!!" It just feels so THEM.