Jake T. Austin would be my Spider-man he's height: 5'8, he has abs, a smart look, humor, he is 20, Almost 21. Looks like Spider-man. Can easy pull of a 15 year old.
Chloë Grace Moretz is 18, Looks like Gwen Stacey, i an amazing actress, and can pull of 15 easily too.
Matthew McConaughey (almost 46) as Norman Osborn/Green Goblin (Villain in the first movie)
Sally Fields as Aunt May
Timotheé Chalamet (20) as harry Osborn/ Kid Goblin (Villain in Third movie (Sinister 6)
Emma Watson (25) as Mary Jane Watson, she can easily look 15, she is a woman, so she can be great as a love interest for Peter Parker in the third and fourth movie, in the first movie just a classmate. Introduce her good in the second movie.
Justin Bieber (21) as Flash Thompson/ Argent Anti Venom (Help after the middle of the fourth movie, with villain Venom and Carnage. He must Support Spider-man
Tom Hanks as Uncle Ben
That are the Main Characters, now in the second movie, Eddie Brock will be in Spider-man but not yet as a villain, the villain would be Mysterio
David Tennant as Mysterio
In the third movie with the sinister 6, Kid Goblin, Shocker, Electro, Lizard, Doctor Octopus and Vulture are the villains.
John Cena as Shocker
Denzel Washington as Electro
Nicolas Cage as Lizard
Ray Liotta as Doctor Octopus
John Malkovich as Vulture
In the fourd movie the villains would be Venom and Carnage
Liam Hemsworth (25) as Eddie Brock/Venom. He can't look to old, he can be older, but Eddie Brock is Peter's closest Childhood friend, so make him like 20 or 21 years old in the movie, when Spider-man is just graduated. (Fourd movie so he would be graduated)
Gregg Suklin as Carnage (23), he is young but maybe in the fourd movie he will look older, Cletus Kassady must be around 25 years old, a killer. Start it off with Spider-man fighting Venom, then Carnage, not thogetter, later Venom and Carnage toghetter, but almost at the end, Venom fights Carnage and Spider-man, Carnage wins against Venom, then Spider-man sees it's Eddie his former childhood friend and fights Carnage.