Can I pause or skip from the Lock Screen?

Yes, with Pro. While a video plays in the background, your iPhone shows playback controls on the Lock Screen and in Control Center. They are Apple's controls. They have play, pause and next.

Next plays the next video in your SkipTube queue. Headphones with a button use the same controls.

Free plan: the video pauses when you lock the phone, so there is nothing to control. See Background play.

To find Control Center, see Apple's iPhone User Guide.