I have two custom templets in /Users/Jason/Movies/Apple Motion.localized/Titles. Neither is showing up in the titles section of Final Cut. I have restarted.

As I suspected, you are missing a level in the hierarchy.

Create a folder inside Titles, give it any name you like, for example, "My Titles" - the name you choose is the name of the Category where the titles will appear in FCP browser - and move the two folders Alex4D and SlideShow into that new folder.

So instead of ... Titles/Alex4D

it will become Titles/My Titles/Alex4D

etc

The following example is for a transition, not a title, but the same principles apply.

In this example, "Lichinho" is the category and "Asym Dissolve" is the particular template.

If the template were directly inside the Transitions folder, it would not work.

(Note: the ".localized" extension is present, but is not shown by default, as you probably already know)

Please show the full path to one of these titles in Column View.

One common mistake is to omit a "category" folder between "Titles.localized" and the actual folder for the title...