Whoa, whoa, whoa. No guys. Just no. Arceus and Darkrai are BANNED AS HELL because they are Uber, so having them on a Monotype team will NOT WORK on Showdown. Find two replacements for those. As for things you can actually use...
Weavile's insanely fast and thus does not require a Scarf. There are far better moves than Aerial Ace. Try something like:
Weavile@Life Orb
Adamant/Jolly
252 Attack, 252 Speed, 4 HP
-Fake Out
-Ice Shard/Ice Punch
-Night Slash/Knock Off
-Low Kick
Standard lead Weavile. Fake Out is always a great option, Ice Shard or Ice Punch are good for either getting priority damage or just straight-up murdering something, your preference here. Night Slash or Knock Off for Dark STAB, again for your preference. Knock Off is a great initial hit since everything has an item. Low Kick is immensely powerful against heavy things that come in on you, like Ferrothorn.
Absol can go mixed, yes. Haven't tried a mixed Mega Absol yet, but I can say that with the heavy amount of Special damage you have on the team already, you'll probably want it to go physical. Try something like this:
Absol@Absolite
(insert Absol ability) ->Magic Bounce
Jolly
252 Attack, 252 Speed, 4 HP
-Swords Dance
-Sucker Punch/Night Slash
-Psycho Cut
-Play Rough
Lots of options on Absol. Swords Dance makes you insanely strong and with Magic Bounce, no one can stop you. Sucker Punch is powerful priority, but I'd personally drop it for Night Slash sine Sucker Punch is easy to bait out once revealed. Foul Play is good, but since it works better if the enemy has stronger attack, I'd again go with Night Slash as reliable damage, plus a crit chance! Psycho cut is good for taking care of the Fighting types slower than you(which is most of them). Play Rough is good for stopping them as well, but now you can also take care of other Dark types. Absol has a pretty expansive movepool though, so there's lots of room to experiment!
Zoroark is pretty close there, but let's just fix it a little bit.
Zoroark@Life Orb
Illusion
Hasty/Naive
252 Speed, 212 Special Attack, 44 Attack
-Nasty Plot
-Sucker Punch
-Night Daze/Dark Pulse
-Flamethrower
I don't do too much Zoroark, but this should be close to standard. The Attack EVs allow Sucker Punch to hit harder. Zoroark can force a switch easily enough with Illusion, which is enough to buy you a free Nasty Plot on the switch. From there, you take your Dark STAB of choice from Night Daze and Dark Pulse and begin to wreck shop. Flamethrower takes care of stuff that would otherwise resist you. If you wanted, you could forego Sucker Punch and Attack EVs altogether and replace it with Grass Knot or Focus Blast. Hidden Power Ice could work, additionally.
Hydreigon is fairly solid, but could also use a minor tweak.
Hydreigon@Expert Belt
Levitate
Timid
252 Special Attack, 252 Speed, 4 HP/Special Defense
-Dark Pulse
-Dragon Pulse/Draco Meteor
-Earth Power/Any of the below
-Fire Blast/Surf/Charge Beam/Focus Blast
Hydreigon has a few Special toys it can play with. Your choice of STAB between Dragon Pulse and Draco Meteor, although if you Scarf Hydreigon, it can revenge kill like a boss and just Draco Meteor and switch. Expert Belt helps bluff a choice set and isn't too much of a drop from Life Orb, although you can use that if you wish. Pick of the litter for the last two moves between the options listed, though I'd personally go for Earth Power and either Fire Blast or Surf. Flamethrower can be used in lieu of Fire Blast if you don't like the accuracy.
But yeah, Ubers ARE banned on Smogon's Monotype, so keep that in mind. Some Dark types to consider are
Sableye, Crawdaunt, Sharpedo, Greninja, Umbreon, Krookodile, (Mega?)Tyranitar, and (Mega?)Houndoom.