Don't waste your time :)

But if you insist on spending valuable resources you could be better using to progress in other areas, I guess Arbiter + Ma'Shalled + Yoshi + Wukong would be okay.

If your going to speed tune the team.....I would go like

Arbiter fastest and lead

Ma Shalled second fastest to give the speed  boost

Dracco 3rd fastest to debuff

last would be Gembo (not sure thats spelled correctly) the  ninja guy to NUKE

Genbo*.  Gembo is too close to Gumbo for my liking and that makes me hungry and it's your fault.

First off, I wouldn't waste too much resources on this. Beat the teams you match up well against and then just take down the one person teams. But if you want to try and make a push in arena this is what I would say. 

With WuKong I get excited whenever I see someone running dymitha because she is a wasted champion against my team. I am just going to steal her block damage. 

Your issue with a speed team is going to be stoneskin. You can run witch but you have a 50/50 chance of the remove stoneskin failing. For that reason I would run WuKong. That way, if your initial string of attacks fails you have some viability to stay in the match.

Here is how I could see the team.

1. Open with Arbiter to speed and attack buff.

2. Have Wukong go 2nd to remove any stoneskins

3. Draco for the debuff

4. Genbo to blow up the team. 

Your other option is to have a lockdown team. Especially with WuKong if you want you could lock down a team really well making it difficult for them to do anything. You just need to make sure you can survive as a go 2nd team. For that I would use Rhonda for her block active and passive and as your hammer to to do damage, WuKong to debuff and sheep, Ma,Shalled for the true fear and buffs, and then probably arbiter but you could go with dymitha. Just know if they have Wukong your team might fail.