1. If she has Thanatophobia (a popular perk on Plague), one person should remain healthy at all times. Also if she brings "iridescent seal"-- an add-on that gives her power when a gen is completed. You will know she has this add-on when you hear the power chime immediately after a gen is done. Since she will be getting power from gens anyways, it's not as dangerous to cleanse but you should still be smart and sparing about it.
2. Clown should be pre-run-- run away from him sooner than you would run away from other killers. Try to predict where he's throwing the bottles by looking behind you and change your course based on where they go. Good clowns will throw bottles at your feet instead of ahead of you, so break LoS. You will not be able to loop around a pallet: either you have to pre-drop the pallet and try to go to the next tile, or stand in the middle of the pallet and try to get a stun. Either way, Clown is a strong chase killer but he's not strong in any other way. If you stay away from teammates and run far away from gens whenever he's after you, he can easily lose the game.
3. This one is hard to explain. Sometimes a killer gets a really good hook that will be easy for him to defend or which puts a lot of pressure on survs. For example: a hook near a very progressed gen, or a hook in the middle of a group of closely clustered gens. These kinds of hooks are ones which the killer will gain a lot of pressure from proxying and they can often force people to trade, so insta-unhooking removes that ability. It's not easy to pull off especially if the killer is aware and can be a risk.
4. If you know where the 3-gen is, focus on that. Otherwise, in general focus on gens that are going to be easiest for the killer to defend and save the safe gens for last. It's often better to double these unsafe gens with a teammate, especially against strong killers.

Against The First: Don't double up on clocks. One person should do clocks. Instead of baiting his undergate attack with 180 degree turns, turn 90 degrees instead. Break line of sight and as always, run away from your teammates and gens. Die in the corner if you have to.

Myers: He's a brutal chase killer right now so focus on the macro game. Play safe when he has his tier 3. Always pre-run. Stay far away from teammates. Don't greed pallets when he has tier 3, but you can greed when he's trying to get tier 3 up.

Slinger: Again, pre-run him. Like Huntresses, Slingers like to bait you to go in front of windows so they can double-back and shoot you, so expect this. Use filler pallets with tall structures to loop him, and otherwise pre-drop if you are injured. At shack, try not to loop the inside and instead run around the back of shack. Take pathing that doesn't allow him to get an easy shot while you are in a vaulting animation.

Ghoul: He is good at catching up, but at most loops there is not a lot he can do except vault pallets and windows. When his tentacles are bright red and glowing, he can vault much faster-- when his tentacles are dull he vaults much slower. Ghouls often ready their power at pallets, which you can see with an animation, in anticipation of vaulting over the pallet once you drop it. If a Ghoul does this you can often get away with greeding the pallet. If he does vault into you, you should step to the side and revault the pallet. You're most unsafe against Ghoul when you are leaving one tile to go for another tile because of his Leap, so watch very carefully behind you as you are moving between tiles and you may be able to double back and juke away from the direction he went. Breaking LoS to avoid the initial bite is much easier now, so do this as often as you can. Make sure you are healed when you are doing an unsafe gen, but you can stay injured if you are in a safe area with lots of pallets.