So in the absence of anyone able to help, I figured some of it out myself. To get the data showing I needed to make the following SQL queries:
Code:
alter table MYDB_jem_register ADD COLUMN `status` tinyint(3) NOT NULL default '1', ADD COLUMN `comment` varchar(255) DEFAULT '', ADD KEY `idx_event_status` (`event`,`status`);
alter table MYDB_jem_events ADD COLUMN `unregistra_until` int(11) NOT NULL default '0', CHANGE column `recurrence_interval` `recurrence_number` int(2) NOT NULL default '0';
"MYDB" is the name of the Joomla database, obviously enough. That changed them enough that they now match the basic JEM 2.2 formatting and I can see my event data.
