This will have their full legal name, address and EIN.If they check a box indicating that they are a corporation, then you do not have to send them a 1099, but it does not hurt anything to do so and I always do it anyways.LLCs, Sole Proprietors and pretty much anybody other than an S or C Corporation should get a 1099.

@Steve RomanoNote that if you create a Pennsylvania LLC, you can ask the IRS to tax it as a partnership/sole-proprietor, S-Corp, or a C-Corp.

If I'm a sole proprietor this year, but get smart and form a single member LLC next year for my self employed earned income, can I use the same 401(k), or will I need to start a new one?

If you did it as a proprietor, LLC, S Corp, or Inc are treated differently.Let me know how you set up the company and I would be happy to help.

My question is, should i file for an LLC while i am educating myself  or stay as a sole proprietor and wait until I get my first property?  

That means I file 1099s to individuals , LLCs, partnerships, sole proprietor etc.- it really isn’t that time consuming or expensive. 

., but not if it's an LLC, or sole proprietor.

Regarding your question: The court in the past have looked at these intents:  The agreement between the parties and their conduct in executing its terms; The contributions, if any, that each party makes to the venture;Control over income and capital and the right of each party to make withdrawals;Whether the parties are co-proprietors who share in net profits and have an obligation to share losses;Whether business was conducted in the joint names of the parties;Whether the parties held themselves out as joint venturers; andWhether separate books of account were maintained for the venture.In more complicated cases, the court has ruled what you are expecting, but there were some significant differences. 

@John Franczyk on the tax front, there is no expense you cant write off, or business tax benefit that cant be taken weather you are an LLC or a sole proprietor historically, its all pass through anyway, for example if you have a HELOC on your personal home, and use the money for business purposes, the interest and expenses are deductible as a  business expense. at the end of the day it makes no difference, unless you are avoiding  SE and filing as an S-Corp, but thats for active income, not passive.

@Greg SmithAssuming you are the sole owner of the LLC, the IRS sees this as a "disregarded entity" - meaning it basically still sees it as a sole proprietor.