Oh boi... where do I even begin...
If you think there is 1 giant server that hosts all the currently played games in LoL, and every single player who is playing is sending and receiving packets from the same IP address, then this is where you're already fundamentally wrong.
Every game is hosted on a Server. This server runs a magnitude of services. Those services communicate with each player connected to that game. They listen for the player input and send back the result and what other players do.
As long as you are in the lobby, this server is not yet identified, as to where the game will take place. Then as soon as the loading screen starts, a new Game ID is created. This game ID uniquely identifies the current game you are in. This is how yo u can look up certain games online, or determine if a player is currently in a game (e.g. on LolSumo) - using that game ID.
You pinging while in champion select means you are testing your connection to the server where champion select takes place. However, no game has started yet. And also no Game ID has been created yet. Hence, as long as you are in champ select, you cannot use the RiotAPI or an app like LoLSumo to check your opponents, because the game hasn't been created yet.
This has absolutely nothing to do with whether exploits work or not.
If you're using exploits, all you need to do is use Wireshark or Cain&Abel, follow where you send your game packets to or where you get them from, and you can find out the IP of the server you're connected to.
Then if you're witty and malicious, you modify the packets you are sending or you send fake packets to that server which every single player in your game is connected to, and let the server process your input.