I would go with Tobi Beers linkify plugin:
http://linkify.tiddlyspot.com/
(be sure to read the whole docs there!)
eg: if you modify every tiddler that contains a name, and you change
the e-mail address in the future, you'll need to do the work again.
And ... it will be more complicated!
If you use the plugin just create a new tiddler eg: Ola Nordmann that
conatins some clickable contact info. If anything chages, just one
tiddler needs to be changed. With a propper configuration imo this
approach will be future proof.
just my 2cents
have fun!
mario