To enter Yahrtzeit information in CMS, do the following.
When showing the list of Yahrtzeits on the Occasions tab, the deceased name and yahrtzeit date will appear on any of the contact records who are observing the yahrtzeit (being notified) regardless if the deceased person is listed in the Family of the correct contact, or if it is linked using relationships.
When more than one person in the same Family is observing the same yahrtzeit (as in the above screenshot), you can click the "Hide Yahrtzeit Observed By" check box to hide the Observed By info and suppress duplicated rows in the list.
Below is the result when hiding this info.
Note: When upgrading past version 15.5.31 (where the above was implemented) past Yahrtzeit information is automatically converted into the new Yahrtzeit tracking system. However, in some cases, due to incomplete or inaccurate information, some Yahrtzeit records will not be converted. After running this update, to export a list of the incomplete/inaccurate info, click Tasks > Maintenance > 'Bad' Yahrtzeits. You can then manually enter this information. Most likely examples of incomplete records are missing date or relation information, or if the Him/Her field indicated a relation to the primary contact who does not exist.