I’ve never created titles for a FCP project this way before. However, after thinking about multiple titles and InDesign’s ability to datamerge, I think that it could be a good fit. You just need to tweak the color settings as it defaults to print production which uses CMYK color space. Having said that, for 1/2 HD I would try a document setup with 960×720 pixels. (You’ll need to change the measurement preferences before making the new document, because the default setting is inches inches.) Lastly, you’ll need to export to a raster document such as jpg or tif in order to import into FCP. Good Luck!
Tech-T Productions
http://www.technical-t.com