For the extruder that is a symptom of a disconnected wire. If everything checks out swap the extruder driver with another axis.
On the bed leveling, I use m3, or 6-32 and lock nuts. The bed literally only needs to be leveled one time, I have never releveled a bed without a full machine rebuild. I see lots of thumbs screws and wing nuts all kinds of leveling gadgets, they all seem to move eventually. You only need to level one time so a screw and lock nut might not be the fastest solution but mine never move. Don’t get this confused with the x axis, that gets out of whack all the time if your are feeding filament too fast or get a clog and have to take of the nozzle, but the bed should never move.
What is the rattle? The machine should be very quiet and smooth. Rattle is all bad, maybe a bad bearing, try rotating the smooth rod.