As your topic said, P2P, meaning it is pair-to-pair trading which means most of the time, but in this case, you may not trust the buyer, a middle person is always needed and it has to be a trusted person to avoid scam attempts by any of the traders. Most of the trades that happen here require an escrow (middle man) to ease transactions and sometimes, people do trust the other traders due to the reputation they built here but the bounty hunters are always clear of cheating, you hardly see them use an escrow or trade here on bitcointalk and you expect people to believe you.
In my OP by local buyer, I mean buyer from his local community. In my country we have many crypto buy sell groups where people buy and sell crypto at their own risk and group admin became the middle man. Sometimes scamming happens with these type of transaction but people still do trade here in these way. Personally I do not use these methods though I know some buyer that's why I suggest bounty hunters to use P2P methods through any reputable crypto exchange.
it is possible and logical that some hunters could sell their crypto to that same buyer.
It is very possible and is considered in different cases, I'm on DT2 and I consider it. I've also seen threads were users were accused of being alts due to related blockchain transaction, but it was quickly debunked as being too vague to serve as evidence; A case by case basis, sort of.
If you come acirsee such threads and go through the evidence, you can aseell consider them and comment or tag based on your conclusions.
It is very hard to determine who is telling the truth. Though I think most of them are actually multi-users and bring all of their tokens in a single wallet before selling them without knowing they could be caught. Still, I think there are a few who actually unaware of these circumstances and made that mistake. Later they failed to provide any solid proof and TBH proofs can also be fake and made so I do not want to defend anyone regarding this concern. Just create these threads so that some newbies can be careful when doing such things.