The biggest reason why you can't get everyone in one go is that if there was a way to do that, then everyone would look up a guide on how to do it and they'd stop making choices themselves. That's an issue I had with the Persona games, you can do all the social links in one playthrough but doing so requires sticking to a very strict guide and at that point you're on autopilot. You stop playing the game the way it was intended.
We try to keep everything balanced so that there isn't an optimal background, or a best guest to choose to manage the lounge, what side quests you choose in 0.5 and so on, and even when you get the "best solution" to how to deal with argos, for example, there's always a trade-off or consequence tied to it, so that even if you know what's coming it's still a meaningful decision.
To answer your other question, yes, MH was originally a quest on an image board where Minoanon would make a post advancing the story and the other anons would reply what the Mc did next, or throw ideas for characters. It's very rough by nature of being written post by post and making shit up as it goes, and full of spoilers of course. I think it's a neat idea to add info on the wiki about how characters changed when jumping from one medium to the other (Luke was a quadruped, good luck showing that on a visual novel format) but I wouldn't recommend reading the original quest because it kind of diminishes the experience. Argos wasn't even in it, and he's an absolutely integral character to this iteration of the story.