As team president, whenever I see a teammate during school who is working on a task I ask for an update. A few seconds can tell you if they are making progress or not. And if they forget it is a quick reminder. Usually once or twice a week works great.
A lot of your problems seem to come from too many people sitting around. Some suggest "weeding"
, you might try giving them something to do like learn Inventor
. A team can never have too many people know basic skills.
-Will