No, it should go about 1/2 to 3/4 of the way down to the bottom of the bowl.
The main drain is plugged. You may need to remove the toilet and snake directly down the drain.
Usually toilet flange is glued down onto plastic drain pipe. There is a toilet flange that can be glued inside of plastic drain pipe also.
It goes down the toilet but if you go in the sink it goes down the drain.
By plumbing codes, no.
The drain is getting plugged and the toilet is lower than the washing machine drain so it is easier for the water to come up in the toilet than to go straight out the drain. Put some drain cleaner down the drain where the washing machine drains and that may solve the problem.
Do the rest of the fixtures in the bathroom drain well? If they do not drain well, my guess would be the venting of the plumbing system. If all of the other fixtures in the bathroom drain well, then there is probably something in the trapway of the toilet. Assuming it is just the toilet that is having problems, then a closet auger might do the trick. Hope it helps.
the reason why the toilet makes noise when you turn water on is because all the water lines are conected so when you turn on water the toilet gets affected and the water that goes down a drain goes to the water pipe.
The sewer line is plugged or collasped. The sink and bathtub may drain because they drain at a slower rate. Toilet is all at once and the drain can't handle it. Water has to go somewhere so it backs up in the sink and tub.
either the vert is plugged and there is no air getting through or there is no vent at all
Actually No, a Goldfish cannot swim back up the toilet. The construction of the trap (the "hole" in the bottom of the fixture) prevents water from backing up into the toilet (see links for a picture). the only way this might be possible is if the toilet is clogged. (the water can't go down the drain and overflows)
Both dishwasher and toilet are sharing the same outlet pipe/drain it is possible when disahwasher is in use it is blocking of the drain somehow so the toilet water has nowhere to go - you need to have a look at the outlet pipe of the toilet and dishwasher the problem lies in a conflict there.
There should be no reason the toilet would overflow. The water being turned off should have no effect on it. As long as the drain is clear even if the shut off valve in the tank didn't work, the water will just go down the drain.