Aaron,
+1 for the ScotchGuard.
We had a job to supply 350 speakers to a racecourse in the far east. Average 98% humidity and average temperatures of 100. They were all treated with the product. I can confirm that they were still working 15 years later. Depending on how much you spray, it will change the sound a little. But not by very much. Of more concern is the wood in wooden cabs. A lacquer coating is worthwhile. Also attend to connectors etc. A blob of silicon sealant works well.
Iain.
edit: missed your latest post while I was writing this one. Have a look at the AE2 cones. I seem to remember Ken Deloria saying that they were coated. If they were in someone elses care before you, they might well not have the original cone. Using the ScotchGuard will increase the moving mass Mmd, you will have the slightest loss of the upper range of the driver.