I think that it would not be bad for an independent expert to be created on the form who will check all created bounty topics and those that in his opinion are fraudulent, let him delete it. And it would also be nice if each project would take something more serious about identity verification, so that unscrupulous program participants could not participate in several accounts at once.
I believe that what you listed is not all workaround, the first of course yes, it would be very cool but, accordingly, users who do not know how to choose projects would start participating in good projects, thereby taking profits from those who have long been in this system. And on the account of the second punk, I do not agree with you, because its stupid, the project will not get any worse from the fact that the same person reposted in two of his tweeters, but simply gives the smarter participant more money.