Alice is probably someone's mom, can't really tell tbh
Xiao means small or young as mentioned so naturally, it can be used from a position of power to degrade the person you're talking too (basically saying that he/she is ignorant or weak)
Idk if this is mentioned before, but Lu Ren Jia 路人甲 literally means Passerby A, and is used to call characters which have no impact. Idk if Zhao Yu calls himself 路人甲 or some stupidly punny variant like... idk 陆仁贾? But basically, no one will take you seriously or think that it's your real name. I mean, imagine asking someone what that person's name is and the reply you get is something along the lines of, "I'm just a random passerby." You won't think that "random passerby" is his/her name, right? That line is actually pretty cringy too lol... Anyway, point is, that's why he says that he would rather be an "Ordinary Lu Ren Jia" and his bro mocks that. I'm surprised that he has been actually treating Lu Ren Jia as his name tho.... I always thought that he used the phrase as a nickname or a blatantly obvious pseudonym or something....
Regarding the story overall, I don't think it's right to say that there is little romance, at least from the chapters so far. I do agree that it's more of a coming-of-age and slowburner kind of manhua tho; it's so short that's what it's gonna feel like. I'm reading this for their backstories so I guess I'm still in for the ride.