The septic tank has nothing to do with the mold in the toilet, the mold that you have is a bacterial growth common to toilets, the toilet needs to be cleaned more often or a stronger cleaner needs to be used, the septic tank is a holding tank for gray water.
Mold grows anywhere there is humidity and warmer temperatures. More then likely it's not mold, it's probably just algae if it's IN the water. It's natural when you have well water. You don't really need to worry about it as you can just clean it out with just a brush and water a few times a year. You don't want to put any "Tank Cleaner" chemicals in the tank or toilet bowl if you have a septic tank as it could kill the "Good" bacteria in your septic tank and you could have all kinds of problems.
The home septic tank is for sewage waste that grey water is also stored in. Grey Water is technically just waste water from your sinks, showers, etc.
In an RV you usually have a sewage waste tank separate form a Grey Water tank as you can empty the untreated grey water into most any drain. Where as the sewage waste HAS to be emptied into a regulated sewage waste disposal site.
That would depend on how far it was to the septic tank.
An RV toilet is designed to be mounted over a holding tank. They use almost no water which at first might sound appealing, but unless you have a septic tank under your bathroom it would be bad news for home installation. Unless modified, an RV toilet would not be able to get the solid waste to your home septic system. A home toilet uses the force of the water to move the solid waste to your septic tank. Look for a low flush toilet or a composting toilet instead.
wrong stuff placed in the toilet
This all depends on the condition of the septic tank. Its like asking, how long is a piece of string
Yes
Ideally 1/4" per foot minimum
You need an upflush toilet.
You need your septic tank cleaned out.
Performing routine septic tank maintenance will prevent your septic tank from backing up and flooding your yard. If a septic tank backup happens, it could cost you thousands of dollars to fix. Use a septic tank kit that you can pour down the toilet once a month. It will contain the necessary enzymes needed to breakdown solid waste material inside the septic tank, keeping fluid flowing freely through the drainpipe. Avoid disposing of materials such as Q-tips, tampons or excessive toilet paper, as these items will clog your system and are hard to break down. Consider using septic system safe toilet paper.
If you really mean it flushes but the water does not run away, then the septic tank is plugged.
My cats play with toilet paper. They scratch it, unroll it and roll in it. I can't get them to stop, but they don't eat it. You have a strange CAT. Septic Safe toilet paper is recycled paper with no chemicals. Should be safe to eat as long as it hasn't been used in the toilet or septic tank.
The drain is plugged between the tub and the sewer or septic or in the case of the septic system, the tank may be full. The toilet had to go somewhere and the tub was available.