The "einige" simply means some.

The word "aus" goes together with "werden". I'll give a few examples.

"Aus dir wird ein Feuerwehrmann" -- "You will become a firefighter"

"Aus diesem Gemüse wird Gemüsesuppe." -- "These vegetables will become vegetable soup."

In many (all?) of these cases, the "aus" can be omitted. "Du wirst ein Feuerwehrmann." "Ja, einige werden Männer.", "Dieses Gemüse wird Gemüsesuppe."

My translation would be, "Ja, einige werden Männer."

The "aus" is not wrong, but only explainable with context which is not given. The "aus" puts more emphasis on the metamorphosis to develop into sth.