To be honest, it's completely unclear what criteria should be used for judging. What does "the most beautiful messages in the chat" even mean? Is it about the ability to arrange emojis, say beautiful things (like quotes or poems), or the ability to express one's opinion competently on current issues?
(The same question applies to "best forum writer.")
"Best topic" is also unclear; again, how should we understand this? Perhaps it would be better to call it "most popular topic," as there would at least be some criteria (number of views, number of posts).
And how will we evaluate the "best guy" and "best girl"? Based on photos, as has already been suggested, or based on their usefulness on the forum? Or should we also add activity as a criterion? In general, this nomination could be presented as, for example, "person of the year," and then it wouldn't matter whether it's a girl or a guy. And we could evaluate them based on their contribution to the forum's development (activity and usefulness).
Overall, the idea is not bad; I always like something new and original, but some details need to be clarified first, and then we can move forward!
Good luck to Raider in promoting the topic!

P.S. What I wrote above is just my opinion.