Novellas or editing?

Question for all my wordsmiths out there. I have two novellas, one is about 30,000 words and the other about 40,000. Would you keep them as novellas or go back and edit and stretch it until the word count hits 50.000? I told the stories, but maybe I could add more dialogue. I am always afraid of being too wordy. I tried the old kiss method – Keep It Simple Stupid, as i was taught years ago. I am sure I need to edit anyway. But looking into a publishing company who is searching for 50K words. Do I try to extend the plot or keep it as is and publish as a novella? My original idea was to combine a few short stories together to make a longer book. Thoughts?