Andrew, as it appears you've already ascertained, neither simple placing nor InDesign's built-in Data Merge will accommodate the live-updating scenario you desire. You do indeed need a catalog plug-in for that. I have no experience with those you mentioned, but Woodwing's Smart Catalog does what you want. I used it to populate the table cells in this document:
http://www.garland-group.com/docs/uploaded/gar/products/A_ALL_PB_USASEPT08_...