As long as it is bolted down solid, it does not have to be level. The problem comes from people sitting on it and rocking or trying to lean to make up for the level.
no it will spurt poo all over the floor in a horrific mess thanks for asking
Wouldn't that depend on the type of toilet valve and where the leak is coming from that would dictate the type of repair?
No.
The wax ring is just to seal the toilet to the drain. It has no effect on the flushing.
By using a level
There's a leak in the pipe.
yes if you eat them
Dye testing
It sounds like a faulty seal, you may need to pull the toilet off the ground and change the seal, they are inexpensive and you can find them anywhere like Home Depot or maybe a place like Walmart. If the seal is broken or not in properly, water will leak from the bottom of the toilet.
yes it does
It can stink if it is not flushed or it is dirty. In some cases, there could be a leak at the base, and the standing water around the toilet has an odor.
It is your toilet that caused the damage and therefore your responsibility.
Depends on how much higher and how the toilet is made. They are not all the same. A PVC flange is supposed to be above the floor level and will clear. They are about 1/4 inch thick. You can probably get away with up to 3/8 of an inch, but any more than that and the toilet will rock on the drain and eventually leak.