I work on notifications on my modules. If you want, I can integrate notifications to your module. I do not know if I have the time today but tomorrow should be fine.
You're right, all versions of xoops offers it. This is the v2 which is new in xoops 2.5.9 ....
The configuration of the captcha should not be done in a file. We will have to be able to configure this in the administration of xoops. This possibility will be integrated in xoops 2.6.