Change the events table to use dynamic types for enhancing the table. Though it is initially more work you are rewarded with gratitude by fellow users who can easily extend the table and by yourself as you can add additional attributes at a later stage.
Alternatively you could use Flexbase which is shipped with Project/Open.
There is a URL field for each activity (not the events, but the root activity) and you should be able to add a presenter and bio by default. Added flexibility would be great but the package should support your needs (if I understand them correctly) as is.
