Hi Mikel,
I hope you take my advice with a grain of salt, but I hope it also helps.
1) Real Estate Agents & Broker's are held to a higher standard in the court of law, so when in doubt DISCLOSE. If you are helping out a home buyer by putting their distressed property under contract (allowing them to get out) and hope to in turn flip the property, I believe you should disclose that you are a licensed broker in the State of California, but you wish to purchase or put the property under contract yourself as an investor for profit. If they fully understand your intentions, there shouldn't be any perceived (in the courts eye) foul play involved. Make sure you get it in writing though!
2) It would be best to discuss your situation for a lawyer to know your needs and get good advice. I am unsure if that is the correct business structure you want to operate under however. In California, there is an $800 fee for an LLC (or a company operating here) per year, plus filing fees but could be worth it. I think that if you want a layer of protection however, I recommend operating under a business license (as well as other benefits).
3) Check out my answer to #1. I think when in doubt, DISCLOSE. I don't know if you are brokering the deal however. I also don't know which contracts would be best, but the CAR contracts are tried and true (they have been through and defined by the legal system, so there is no ambiguity) and WILL hold up in court.
4) I don't know of any, sorry :/
I read from a user here [that i can't remember and give credit for :( ] that wholesales, as well as being a licensed agent. When they get a call from a seller, they try to see if the numbers work, but if not, they offer listing the house for them. This could be an ideal situation solving your issues?
Again, I am absolutely no expert so please take all this with a grain of salt. I hope that it helped somewhat though!