No.
Air is an example of a mixture of gasses.
Brass is an example of a mixture of two solid metals.
No, only liquids. Most liquids can be separated by filtration those which can't are mostly separated by evaporation.
To be considered a solution, it has to be a homogeneous mixture. Where you have liquids, they may not dissolve into one another, such as water and oil, and you have a clear division where the liquids don't mix. Where as gases, is they are in a closed system, are homogeneous because there is nothing there to stop the molecules from occupying a relatively homogeneous arrangement.
A solution
Fat
mixture of polar and nonpolar liquids.
miscible (soluble)
The mixture is homogeneous only when these liquids are miscible.
Miscible liquids are liquids that form a homogeneous mixture when they are added together. Obviously liquids that are immiscible do not form a homogeneous mixture when they are added together.
No, it is a mixture, as they are not liquids.
The temperature that is boils at...
No, it is not two liquids. It is two types of mixtures.
The statement in the question is false. It is very common for two liquids to form a mixture that is also liquid, and, unless a chemical reaction occurs, a mixture of two gases always is also a gas.