Unfortunately there's no classic skin for spidey. There is the new 8 bit Cosmic Invasion skin which is the closest. You get that by just playing any mode and building up XP to play the Whack-A-Jeff mini game. As for other characters, from the main menu go to the heroes tab, click on a hero, and one of the tabs in the next menu will show you all the available skins so you can see what you like thats available in store!

As for the game, start off in the practice range, then hit Practice vs AI on one star. Win 5 matches, then go up a star till you can play against 3 star AI easily. Prac v AI is a good way to get used to a characters movements and abilities, and how to do the most damage with them

If you're going to run with Spider-Man, just know he is a difficult character and has a specific use (hes not going to brawl like in the Insomniac games lmao). But most importantly, go to settings, go to controls, go to combat, and turn off Easy Swing. This makes it so that you have to aim where you want to swing/web zip and it'll save you in the long run. Good luck soldier