You really have to watch each episode two or three times in order to pick up on the subplots, subtext and foreshadowing that become important later.
The Symbiote seems to have two voices, one from the original person, and a second, much darker and more violent voice. The brilliance comes in when you realize it's the same actor as the person wearing it doing the voice each time, to represent that the Symbiote is bringing out the worst aspects of the person it's currently being worn by.
In the beginning of the show, why did Peter have a crush on Sally Avril? Because she bears a slight resemblance to the one he later comes to love the most: Gwen Stacy.
In the prom episode, Harry can be seen in the background applauding Mary Jane for winning Prom Queen. At the same time that the Green Goblin was battling Spider-Man. A nice little bit of foreshadowing.
In Rhino's debut episode, Spiderman points out his one weakness; that his suit is so well isolated it overheats with ease, and needs cooling down regularly; this is actually a problem real-life rhinos have, and they need to refresh/cool down themselves with water or fresh mud, or rest under a tree's shadow, when weather is too hot. Also, in subsequent episodes, Rhino rarely fights on day-time; he fights at night, or when weather is cool enough.
There no way in heck Norman would've had the foresight to frame Harry for the limping leg thing, considering he just stumbled upon the passed-out form of his son after his bout with Spidey in the first season finale. Plus exactly what reason did he have to fake a limp in the first place?
Spider-Man had already accused the Goblin of being Norman. If Gobby had a limp and Norman didn't, it'd throw Spidey off that trail even if he didn't come across a convenient scapegoat.
I don't think crippling Harry was part of a plan. he does describe it as "serendipity"
Part fridge logic and maybe Fridge Horror; Rhinos suit. So, it covers his entire body in a metallic armour, to the point where the only exposed bit of skin is his face and he can only sweat through his face. How does he use the toilet?
He probably has some sort of tube for that.
The comics establish that he has a flap for that.
Spidey using lockers to create a ringing sound that would disrupt Venom... yeah, try hitting a locker with a baseball bat. They don't work like bells, they'd get dented and make a loud, non-ringing sound for less than a second. Artistic License - Physics is pretty much the only way this could work.
It probably helps that Spidey has super strength and therefore hits much harder than a normal person.
It's not the strength that matters, it's the object that's being hit, specifically its shape and the material it's made of.