Yes, Arb into 2 nukers would work as long as you can win the speed race.  Your 4th should likely be a defense down champion, or possibly another turn meter boost if you plan on focusing the nukers on damage (i.e. attack% boots instead of speed).

You already have Sinesha at 60 so I'd use her instead of Tallia, along with Skullcrown as the nukes, with Sinesha going after Skullcrown for her A1 (an extra hit if the target is less than 50% health).  Alternatively, the second nuke could be Ninja with his freeze, which means the enemy wastes another turn.

Something like, Arb --> Decrease Def Champ --> Sinesha/Skullcrown --> Ninja/Sinesha

The other reason I would suggest Sinesha and Ninja is because they are already 60 so you don't need to use resources to build them up

Edit: Do you have Aleksandr from the recent promo?  If so, he would be a good option for decrease defense as he also brings weaken, plus hits quite hard

I don't think these teams will work. With only a single speed booster you will never get your nukers to act in time.

I think you have two options:

1) Arbiter + Gorgorab + Ninja + Zavia. Speed tune so each champ goes right after the other, with the exception of Zavia. Ninja should focus on ACC, since his goal will be to AOE freeze the enemy team. Zavia should be *slow*, so that the enemy team all unfreezes *before* she nukes, so they don't benefit from the damage reduction

2) Miscreated Monster + Vogoth + Skytouched Shaman + Tatura. I think this team will be easier for you to gear, although it will be expensive. The basic idea here is that Vogoth and Skytouched will keep your team alive a really, really long time between the two of them. That being said, it does require quite a bit of gear - 300+ RES on all four of them.