Many of the Meta questions or discussions have comments only. I do not have enough reputation to comment. Does this fact mean that I cannot participate in the many discussion on Meta? Or am I allowed to post answers to discussions in an answer form when it would really be a comment instead?
The comment everywhere privilege enabling you to leave comments on other people's posts is awarded at a reputation of 50. Which you can reach quite fast answering or asking a few questions.
While you're gaining those reputation points feel free to use answers on meta* to discuss issues of your interest. The mods can also convert answers to comments if need be - again just try to not over do it. Be sure to indicate which answer you're refering to.
* unless you start discussions on 200 topics or so.