I recommend doing this in the Hangar 6 R&D dlc if you have it. It is shorter and quite a bit easier than in the main campaign.
You will have a bit of a rough time coming up in the beginning though. The lack of abilities and good weapons will be a challenge but thankfully you don't have to deal with the big fellas yet.
As for the teammates...pick whichever you feel most comfortable with. In my case those were the Commando and the Recon.
The Commando can Taunt which makes the aliens walk straight at him open for attacks. Plasma Field deals some good damage and Pulse Wave pushes aliens away and can knock them prone if they come too close for your taste.
The Recon was my favorite. Critical Strike deals some sweet damage especially when upgraded with Armor Piercer at Rank 4. Diversion can take the heat off of your team so you can plan without laser fire all around you. Fire Mission is essentially an air strike dealing massive area damage.
A few general tips:
- always take out the special aliens first (Shield Commanders, Minion Commanders, Rocket Snipers etc.)
- easiest way to take care of Mutons and Sectopods in my opinion was to Lift them with DaSilva followed up by one of his Demo Charges, Fire Mission with the Recon and Plasma Field with the Commando. Your guns can take care of the rest.
- constantly monitor your teammates since the AI loves to rush into enemy fire getting themselves downed in the process