I'm no botanist but if we use our common sense about stuff that comes on our plants' leaves it is probably a safe bet that the white stuff is mildew---caused from moisture hanging on and when the furnace came on and changed the environment for the better it began to be noticed.
The little insects in the mildew could be nothing more than gnats (fruit flies) that like to eat dead and rotting material.

The concoction you made...with vinegar and lemon juice--was that by chance or have you seen something about it from another source.
I'd try first plain water and a soft cloth putting it between my hands and wiping the leaves down--then pat dry.
I've never heard of such an acid wash being used on tender leaf material and making any good result.

The gnats, if it is indeed that, is due to increased amounts of moisture hanging on and causing increased amounts of dead matter which they then feed on.
The usual approach to this is to not water so much...let your plant dry down more.
Lay some strips of yellow plastic---about a 1/2" - 1" wide over the surface of the soil after coating with some white petroleum jelly. The gnats stick to it, you then wash them off and repeat the film of jelly.
Other than gnats, there are always some bugs that are attracted to dead matter. Washing them off might be the end of them.
I'd try the letting it dry down some---see if that doesn't help reduce the problem.

Scale of some sort, perhaps?

Josh