"They are eating a pizza."
Translation:Ils mangent une pizza.
A mixed group of male and female always takes the masculine form: Ils. Elles is used when speaking about a female group exclusively.
As xsargonx said, an exclusively male or mixed male and female group uses "ils", and "elles" is used for an exclusively female group. Since we can't know which it is from the English sentence, both translations are accepted.
No, you cannot use "vous". "Vous" is only a plural for "You". So wherever you "they" in English is when you cannot say "Vous" in French.
Is there a difference in pronunciation between "il mange une pizza" and "ils mangent une pizza" or is it one of those thongs where you have to rely on context?
You mostly have to rely on context when it is spoken orally, unfortunately. They are both said the same way. I hope this helps :)
Why isn't the French translation 'ce mangent'? I understand that usually a noun comes after Ce and for Il/Elle an adjective comes after but isn't mangent a verb? Does ce also apply when a verb comes after?
Kindly mention the gender whether it is male or female so accordingly we can choose if it is Elles or Ils.