0. I hope this is the right section for this if not I apologise.
1 - Who should I primarily look to employ and how much will they be expecting to be paid?
2 - Who should I have in house and who should I employ for online freelance?
0. Starting a studio = starting a business. (It is not "getting a job.") So I moved this to the (guess what) Business forum.
1. Programmers, artists, designers, audio, testers, business manager, IT. As for payscales, see the 2011 Game Industry Salary Survey (google it) - you may need to adjust for the country where you live.
2. People you cannot keep employed full-time should be contract personnel.
3. You'll also need to get a lawyer on retainer.