it's pretty safe to cook in a solar oven, but it can catch on fire just like any other oven
Solar cookers use direct sunlight to cook food. Some solar cookers use reflectors to cook food, and therefore extreme caution should be used when cooking with them.
No you can't.
Solar power
Not always. Some recipes calling for a dutch oven are first heated on the stove top to brown meat before adding other ingredients and placing in the oven. Most "oven safe" dishes are not safe to use on the stove top burners. But it would be safe to brown the meat in a skillet then transfer it to an oven safe dish for oven cooking.
a solar oven works by sun
There are solar ovens available but they have not yet proven to be reliable.
No, you can not use house paint to paint an oven. You must use a high temperature paint
That simply isn't true. You can cook anything in a solar oven - you can even bake cakes or cookies, if the solar oven is well-built. We do that here at my home. However, please note that cooking takes quite a bit longer in a solar oven than on a gas stove, so you may have to plan a bit more in advance.
The use of parchment paper would help prevent burning of marshmallow in an oven in general. This applies to solar ovens and stove ovens.
No, cookies would not bake well on the barbecue.
Yes but I would unplug when it is not in use.
yes, because solar panels use the sun for light.
that depends on what you mean by "better." Solar ovens can operate without any electricity or gas, but then, you cannot use a solar oven at night or on cloudy days. Electric ovens can be set at specific temperatures, which is more difficult to do with solar ovens. Electric ovens cost quite a bit of money, while a solar oven can be made with not much more than a cardboard box and aluminum foil. So it all depends on your circumstances and what you are trying to do.