Does the FPS of the playback matter? I'm trying to edit a video to post on to Youtube and i need the FPS to be 30 so that the audio syncs with the video. In order for me to achieve 30 fps in some parts of the video I have to turn the quality way down. (10% of 720p).

My question is, even if the playback FPS is low, will the render be OK?
Yes, the render will be fine.  Make sure however that you bump up the quality back up to 100%, otherwise it will (just a guess) render an animation 72x128 pixels.  Playback FPS is just the realtime playback speed.  Do keep in mind that your computer may not progress through the render very quickly though.