You have been doing your homework!
To address your questions:
1. There are a lot of excellent real estate agents working in Pasadena. You can do a couple of things. First, ask your friends and family for a recommendation - if they had a great experience with an agent most likely, you will too. Also, use the power of internet to learn more about the agent, or just google pasadena real estate agents, see who comes up and explore their sites. Also, interview your potential agent candidates to ask them about their experience, how they work with consumers, what their specialty is - residential, income, first time buyer, etc. See who you feel more comfortable with.
2. The best way to get a loan is to go through a referral from the agent that you pick. Real estate agents have established relationships with credible and reliable lenders and mortgage brokers. For example, I have a list of several lenders/mortgage brokers that have consistently provided great rates and service to my customers. Most importantly, there were no surprises or last minute changes. That's critical, especially, in today's real estate market.
3. As a buyer, you are in a great position. The seller will pay commissions for you. As far as rebates are concerned, you might be able to find an agent that will give part of their commission back, but if they're willing to give you a portion of their salary, I'm not sure that they would be the ones to negotiate on your behalf. An experienced, full service real estate agent, will not consider that.
Hope this answered your questions. I am putting a link to my website below and it has a lot more information and articles about buying a home in Pasadena and surrounding cities like Sierra Madre and Monrovia. Also there are posts about how to find a great agent.