Re: When the importer puts "{{" around a Mediawiki template, what to do?
I believe the importer leaves the template syntax as-is during the process as Tiki has no direct equivalent.
To link to your JIRAs, you can either create a custom plugin or a plugin alias. Both would result in a syntax that looks like this:
{jira id=STA-12345}
I don't know the exact modification that would be required to modify the installer to do this on the fly.
;){kind=link}
;){kind=link}