We are on PCs working in CS5 and Visio. Using Visio we need to be able to edit/adjust submitted technical drawings created in Visio and then "Place" those native Visio drawings into data sheets (CS5 Indesign/InCopy workflow) without converting or exporting the Visio drawing as a different file format. That includes opening an exported Visio drawing (in a Illustrator-compatible file format) in Illustrator. Working within CS5 InDesign we need to be able to "Edit original" Visio drawings in Visio sent by authors/engineers. Do-able?
Given all of your conditions? No.