Dooku vs Arcann, Senya & Vaylin (sabers only)

If Dooku wins, give the team Marr

If Dooku dies, give him DS Quinlan Vos

If Dooku wins, get rid of Senya

So the fight can become more unbalanced???

Whoops, brain fart 

Give them Marr

Loses both.

Dooku

Loses pretty solidly

No matter how much you wank Dooku no Jedi or Sith who isn't Yoda or Sidious level or above can take on these 3 in a sabers only match

Vaylin is honestly terrible as a combatant, for her power level. Senya is above her, but that still doesn't make her impressive.

I think Dooku has a shot if he manages to remove at least one of those guys rather quickly. If he can get rid of Vaylin fast enough, then he has a good shot at the duo. However, if it goes for too long, Arcann - as inferior to Dooku as he is - should be able to use the other two as leverage useful enough to overpower Dooku due to numbers. 3v1 is an insane scenario, viable only because of the insane skill of Dooku.

Dooku dies hard.

Dooku has already shown himself capable of managing a 1v3 duel while under the effects of Nightsister poison, and has repeatedly tooled seasoned duos in Anakin and Obi-Wan, so this by no means an unwinnable scenario for him. However, it's a bit difficult to rate the dueling skills of cross-era characters like this.