For example if I'm playing a melody that is in f7, while comping with my left hand, do I keep the f (e, f, a, c) or drop it (e, a, c) making it sound like a minor
2 Answers
To the title- yes. For any given melody, there will usually be several different chords that will sound good under it. If you know F7 (or FMaj7) sounds good under it, then chords that share notes with FMaj7, such as Am, are likely candidates to also sound good under it.
To the question in the body, it depends what your goal is. If you want to play the harmony as written, dropping the F will make it sound like Am and you have not achieved your goal. If you're in a band setting with a bassist that will be playing an F there, it may become safe to drop the root. If you just want to play music that sounds good, you can pick from the several different chords mentioned earlier.
Keep the F in the left hand. The melody would generally be moving more than its harmonic counterpart. Many of the right-hand notes would not be F. Something needs to describe FMaj7 (what I believe you really meant) consistently. Otherwise, you would be right in saying that it's A-Minor.