Every year players write guides to this thing. To find them, try a Google search such as punkin king farm site:forums.spiralknights.com. Now to answer your questions:
1. Yes, as Flowchart said.
2. Fast weapons are valuable. You want to score lots of little hits.
3. I don't know, but so far it seems to me that scarabs might be appearing more often with lower candy payout per scarab. But take that with a grain of salt. I might be misremembering previous years.
4. As Flowchart said.
5. I do think that flourishes are pretty effective. They're not slow, but they have a wide first stroke. Just use the first stroke.
1. yes but might be tricky to hit, maybe aim at the shadow.
2. probably easier to hit him with faster guns than a blitz but I usually use swords for this. Although it seems to help if you have someone else with a shiv and then fire a blitz charge just as his trick begins.
3. They're fairly rare but you should probably get at least 1 or 2 per graveyard, maybe more. The graveyard ones are the only way of getting Brittle candy for the scarab mask (besides prestige rewards/buying them) so if you don't have everything yet you'd want to do both.
4. It's like the regular prestige missions, you can only get the rewards once per day, but you can go through it again if someone invites you.
5. caliburs are good enough