I'm not familiar with the products you mention, but I understand that Azomite is a montmorillonite containing colloidal minerals. Montmorillonite is a clay formed by either weathering or sedimentary processes. Speaking purely as a soil scientist, chemically it contains a bit of Mg and Ca, with little of other nutrients, contradicting what Azomite says it is. For us in WA montmorillonite is the reflection of weathered soils. Rock dust is the unweathered material containing all the good stuff, prior to weathering.
Rock dust can, depending on conditions, head towards montmorillonite.
Mixing rock dust and Azomite seems harmless enough, but I don't know enough to really say. Reapplication is a good question. I'm attempting to come up with some predictive tools. We had a guy here who grew tomotoes straight in rock dust successfully, so ovedoing it doesn't seem a problem. Our major concnern with application rates involves trace elements.