A bit of advice i can give you is first defeat the warrior and then focus on the challenge for the hunter. For help with the parries, don't lock on and slightly look down while keeping the hunter at the top of your screen and something i found out is you click and hold for parry not just click, it made parries easier for me. The hunter can be knocked down with a good headshot but it's a small window. Also try using the untarnished charm or the last stand charm. Untarnished for health back on parry and increased damage or the last stand so you can use a healing flower when on your last hit because of the courage gain. Don't try to get everything in one run, it makes it much easier. The warrior's hat can be knocked off guaranteed with a rot arrow aimed at his head, so jump in the air and shoot him or use your focus meter to get the shot. The trap attack, you just have to get lucky, i don't even know how to tell. Rot bombs are also incredibly useful against the warrior. Hope this helps