Easy to do, but can have detrimental effects. The water goes down that line to provide the motive force to keep your waste product moving down the pipe. If not enough water goes down you could have plugging in the line.
yeah
You could have a venting issue with your venting system, or a blockage with your main line. Your toilets dump alot of water all at once. Try to visualize all that water hitting a closed bubble of air in the pipes--that is why they could all be flushing oddly.
adjust the floating bulb, it may be running over the top of the overflow pipe
The bath filler waste is directly connected to the trap and overflow water is supposed to drain there -it is not a leak.
The continuous going water cycle prevent the rain to stop forever. It is an on going process.
Back water valve
Yes, stop leak turns into a thick substance to plug any leaks, when it ends up in the overflow bottle it turns into sludge there.
if you have water to the rest of the house and its the toilets only then either someone has turned off the valves under the toilets or the fill valves have both failed at the same time. [not very likely!!] cant be much of anything else.
restart your computer, it will clear the overcommitted stack
Teach the garbage dumpers.
your water is starting to break
The thing that the water goes into is called the drain. And the thing you put in it to stop is called a plug.