With the scoreboard open, click on the small bubble with a number in it next to a champion's portrait to ping that champion's level. Clicking on the empty bubble on the other side of the portrait will ping that champion's ultimate ability.
You can ping caution either by dragging up on the ping wheel (hold alt and left click-drag on the map), or pressing G (by default). The similar retreat ping is done with a ctrl+left click or pressing V. For the enemy vision ping, you can set a hotkey for it in your settings on the "Area Is Warded Ping" row. I'm pretty sure there's no default hotkey.