Welcome to the site!
This thread is really old, in the future just start a new one with your question.
So what exactly are you asking? Can a lesser pastel make a BEL?
Yes it can, just not by itself. You could breed a lesser pastel to any of the following and have a shot at producing a BEL:
mojave
Lesser
butter
As well as any combo morph that includes one of the three morphs I listed above.
There are others as well, but lets not make this too complicated for now.