What to do with a layer that sticks out and doesn't connect with others. First you need to see whether there is a slope to cut the hair on that will simply blend in the lost layer without over-layering. Sometimes you just need to sacrifice some length to get it to work.
|The slope indicated by the pencil is much steeper than I like for cutting waves - overly steep cuts in wavy hair shear off the curve of the wave as you'll see below.|
Just for fun, I re-did the 90° cut:
And the 180° cut:
And this is how I usually cut my hair after I get an outline in which the top lengths do not stick out over the bottom lengths (I do a 45° cut, but it's really free-form, mostly just to make sure the top isn't longer than the bottom, then I do this):