My team is a mix of 2 and 3, we have comp sci, math, actuarial, engineering and physics people with about an even split. Oh and one quant dev who was a medical doctor but found programming more fun. So it's all sorts.
You mentioned actuarial - as an actuary interested in quant work, I'm surprised they are so well-represented on your team. Do you find lots of them in the industry? I'm taking the Quantitative Finance specialty actuarial exams and figured it'd be a long shot to break in, but maybe there's hope.