"Tonight is a lunar eclipse and I was wondering what settings would be best to photograph it?"
The traditional starting point is the Looney 11 Rule. It says using f11, SS 1/100 and ISO 100 you should get a close exposure.
However, this is just a ballpark estimate. You need to bracket your shots a few stops each way for best results.
By 'stock lens' do you mean the standard kit lens ef-s 18-55mm? If it is, you won't be able to get much of a Moon shot with it.
On your Rebel 400mm is probably going to be the lowest FL to use and 600mm will be even better.
Fred Espenak is THE master in not only eclipse photography... but eclipses in general. He's a retired NASA physicist who still (even though he is retired) makes all of NASA's eclipse predictions.
He has a website "Mr. Eclipse" and he provides loads of tips on how to do this:
Just know that the Looney 11 rule applies to when the moon is not eclipsed and enjoys the full light of the Sun. As the moon slips into the Earth's shadow, it will no longer enjoy full sunlight and the exposure needs to be adjusted to compensate.
The page linked above will explain this.
The moon looks nice & large on an APS-C camera at focal lengths of around 1000-1500mm. (At 1500mm it's a really tight squeeze to fit in the frame ... but it's a comfortable fit at 1000-1200mm or so).
Few camera lenses can provide that focal length ... I usually attach the camera to my telescope. But you'll still get some great shots with your lens... but expect the moon to be small in your images.