You'll need some type of dehumidification equipment upstream of the filters: mechanical or chemical. Plenty of choices, the question is which will work with the AHU that's been specified.
I've never used their product, but I did meet them at the AHR show last month, and I have reviewed their literature. I've been impressed with all that I've learned. If their product performs as well in the field as it does in the lab, it should be a home run.
An easy free tool for quickly manipulating and representing different HVAC components is available at http://www.elitesoft.com/web/hvacr/hvacsolution.htm
Good for doing schematics.
Searching the web for air ionizers will return little substance. What you'll find is marketing hype from manufacturers of in-room ionizers.
Ionization can charge particles, but unless these charged particles are captured on a media filter within a forced air system, the particles will attract...