You must look at the phases in your system. Whenever there is only one phase, but there are two or more chemical species, then you have a solution.
Beside this, all the rest is semantic. Some can be regulated by IUPAC, some not.
Refer to air as a solution would sound unusual. A gas mixture - unless reacting to give a liquid or solid product - is always one phase, so the term gaseous solution isn't even considered by the IUPAC's definition of solution: https://goldbook.iupac.org/terms/view/S05746.
About "solid in gas" you are correct, once in the gas phases the iodine or naphthalene vapours aren't solid anymore.
However, note that the same applies to sugar or salt in water. You can certainly speak of a solid (dissolved) in water although the actual solution obviously has no actual solid anymore, and even no salt but ions. In this case, the use is common because it is what operationally we do, we take a spoon of salt and dissolve it, even in the kitchen, and so we speak.
"Solid in gas (or liquid)" as it is and without context would mean smoke (or suspension), so we are not dealing with solutions.
I hope this is clear enough for you to understand that you were somehow over thinking the subject.