I've spent about ten hours stripping down, cleaning, wire brushing, and reassembling the Castle Front's mechanism. Last night I was able to operate it manually and it more-or-less works. The reels spin freely by hand, but the reel kicker would barely impart enough energy to give them a single rotation.
The toe of the reel kicker is really chewed up, so I dropped it off at my favorite metal fab shop at lunchtime today. They're going to remove and replace the whole foot with a piece of mild steel. Here's a picture.
https://photos.app.goo.gl/R4Hm7591mRhZqR742
One of the reel brakes is not with the machine. I found some tempered steel rod of similar diameter and formed it into a reasonable facsimile, but won't be able to test operate it until the kicker is reinstalled.