Applying flammable coating at temperature below its flash point
You should be aware that the just because the temp. of the liquid is below the listed flash point, does not mean that the liquid is not giving off flammable vapors. It means only that it is not giving off enough vapors to reach the low end of its flammable range (LFL- lower flammable limit) concentration in air under specific test conditions. If the conditions you describe were to change, you could have a problem because xylene ignites at a relatively low concentration in air (1% - 6%).

That being said, I think it would be difficult to achieve the LFL concentration (1% for xylene) in a room that small, at that temperature, with a 100cfm fan. The fuel-air mixture would just be too lean.

Don't forget to wear a good respirator rated for organic vapors.