Congrats.... and welcome on DT network.
For my first question, is it cool to give positive trust for transactions that I am not personally involved in?
First I want say you have to more careful about your positive feedback rather than negative feedback. Positive feedback could misuse. I don't see any poin, why you should bother to leave feedback if you are not involved with any transaction or you are not on risk. You can leave your positive feedback who is really touted to you. For example, if you want to leave positive feedback to theymos then there no need made any transaction. Because you trust him personally. Its different case. Same like you can trust LoyceV or suchmoon for any reason. Its fine to leave them positive feedback. But just repaid for loan and you are not involved with it should not leave positive feedback. But if you are lender and if really you think borrower is trusted then you can leave positive feedback. Like you can see my feedback, Darkstar was on risk of 0.03
BTC with me due to drop collateral price. But I returned his loan as well. Hope you understand about it. (It's all my opinion only, may be other DT will not agree with it).
Regarding negative feedback you can follow old DT members who are handling scam/abuse. No one forcing you leave negative or positive feedback. I was leaving feedback even I wasn't on DT.
In my opinion you have to investigate and use reference for negative feedback. Just don't tag if someone made scam post.
but the person launching the complaint doesn't exactly have a pristine reputation and the supporting evidence was less than lackluster.
Doesn't matter who are laughing, I have read that thread and replied as well and that's why I follow The Pharmacist quote.
My suggestion is for OP to grow a thicker skin about these things. If you haven't looked at the trust pages of most DT members, take a look at Lauda's, or Vod's, or even mine.