Can I remove all effects from a sequence?
You sure can but it can be a two or three part process. If you lasso (or shift+click the clips using the Lift/Overwrite Segment Mode tool) around the entire sequence and press delete, it will delete all of the effects in the sequence. (You can also use the Remove Effect function to delete effects.) However, if there are multiple effects on a sequence, it will delete the effect with the highest hierarchy and leave lower hierarchy effects on those clips.