You have a manager arranged?? I think that manager is about to rip you off. LLCs do not require external managers, and do not do the things you think they do. Someone is pulling the wool over your eyes.
You don't need LLCs to do investing. As a tax shelter, single member LLCs do nothing since they are a disregarded entity for tax purposes. They are also useless as a liability shield: the plaintiff can simply put a charging order on the LLC since no innocent members will be harmed.
There is such a thing as a "member managed LLC" (where invested members decide) versus a "manager managed LLC" (where persons/entities are designated as managers and the managers decide how to run the business). Anyone can be chosen as a manager, the law certainly allows you to make stupid mistakes. But the manager of a single member LLC should nearly always the single owner, unless he is incompetent to do so, or the person giving him the capital doesn't trust him (e.g. Trust fund baby).
Even the manager of a multi member LLC should be a member with stake in the business.
Understand something important. Money is not that complicated. But it is a very common scam in finance for "advisors" to make it more complicated than it is: to make you frightened of the complexity, feel like you can't do it yourself, feel like you need them, and make you not ask questions. Inside this fake complexity, they hide their frauds and ripoffs.
If you do not have the skills to manage your inheritance, Then Get The Skills. No one can be trusted with this job, except you. What, are they not paying you enough money to do some learning?
If somebody said "I will give you $10,000, but, in order to collect the money you must learn the fine art of money management", I'd grab my sharp pencil and notepad and hit the books, you betcha! You have that exact same situation, except you need to learn the skill in order to keep the money.
I recommend Dave Ramsey or Suze Orman...
John Bogle's "Common Sense on Mutual Funds" ...
And while not all would agree, I like the Rich Dad Poor Dad series.
As far as investing strategies, shrug, I manage endowments. When someone dies and leaves a university a million dollars, they don't get spend happy. They sock it away in an endowment, which is invested in the market. They withdraw 4-7% a year and use that as needed. And they can do that continuously, forever, because 4-7% will keep up with the stock market. (Well I'd wait for the next recession and buy in when Wall Street is having a 50% off sale.)
Anyway, a typical endowment investment mix is 60% domestic stocks, 10% foreign stocks, 10% bonds 10% real estate 10% cashlikes. The stocks are typically index funds (see Bogle). That's not rocket science, now is it?
And mind you a typical university board of directors is composed of businessmen and some of the best investment bankers on earth. They market annuities and managed funds to suckers, but when it's their money, they keep it simple.