As you can tell, there is no one "right" answer. A lot depends upon your life goals and risk profile. The first friend is nurturing a generations-old wealth. The second is trying to propagate generational wealth. The third is trying to establish generational wealth. If none of your financial advisors have asked you to set down on paper what you want to do in life and how much it will take to fund that ambition, then you might want to center yourself and put that down to draw a starting line in the sand. From there, you can talk to them about how much volatility you can stomach, how much needs to be drawn and when, etc.
It cannot hurt to get second and third opinion advice this early on your tax implications before the sale closes. Bob Hope was famous for deferring a lot of his pay into capital gains forms once he made enough to live on, and this greatly magnified his earnings over the years. If there is a portion of your sale that you are willing to put into that form, then now is the time to talk with your tax advisors about it before a more adverse tax treatment is taken upon your sale income.
If you feel at all uncomfortable with the advice you are receiving (including and especially mine!), then one option is to take the uncomplicated tax treatment hit now and sit on the gains until you are more comfortable with a specific set of actions. There are far worse situations to be in than paying a large tax bill now and parking the remainder into [CDARS](http://www.cdars.com), then taking whatever time you feel is necessary to gather your data and thoughts before you pull the trigger on structuring the gains. As my CPA tells me, some of the biggest tax payments he oversees each year are from clients who are too busy making money to complicate their lives further with tax efficient structuring. The interest alone on say, $10M (after taxes and fees) in CDARS, is around $100K, which should be sufficient for you to step back, take a deep breath for a year, and figure out where you want to go next. Even taking into account the "opportunity costs" of a naive tax treatment, that is really cheap insurance against hastily making a catastrophically bad decision in the heat of the win.
You can also contact pg, he certainly can give you advice programmer-to-programmer.
With this amount of cash, you want them to BID for your business. They will do so by offering proposals.
1) this should be easy to evaluate. it's just math. But, they may want to setup some entities to help you take advantage of the tax laws (eg. capital gains vs income).
2) remember they are commission driven and make money by funneling your "cash" into their brokerages and other services. negotiate. this will be highly dependent on what you want to do with the cash once you have it
Hear them out, choose the best solution / provider
Also, talking to your accountant (assuming you have one) might be a good first step in at least getting recommendations about who to talk to.
I'm not sure why you would need to set up a LP, or LLP unless your startup is just your code and not a legal entity. My email address is in my profile, send me an email if you would like some more help.
I'd definitely be after some professional advice (and making sure they are on your side!).
I assume you may need a lawyer to help guide you through the sale (and they should help catch any BS)?
And, yup, regarding the sale there is a lawyer handling everything.
(a) Comes well-recommended by others in your network
(b) Has successfully handled this sort of transaction before