If you think about it from a logical perspective, let's assume that Jay is a sole proprietor and his self-employment business activity involves It Consulting.

Have any of you made a business name as a sole proprietor without an LLC?

Technically one can have multiple solo 401k plans but it does not make since because of the following:When a self-employed individual maintains more than one trade or business, the questionarises as to whether the limit is based on the sum of earned income or loss from all trades orbusinesses under common control [as defined in IRC 414( c)) as modified by IRC 415(h)], or ifonly the trade or business maintaining the plan being tested is used.For purposes of the IRC 415limit, earned income for the self-employed individual is based on the sum of the earned incomefrom all the controlled trades or businesses, regardless of whether the related employer maintainsa qualified plan [Reg. 1.415-2(d)(6)].EXAMPLE: Andy, a sole proprietor, operates a law practice as a sole proprietorand has $100,000 of self-employment income from such practice for 2008 (prior tothe reduction for one-half of self-employment tax).

What that really means will differ based on the type of entity (sole proprietor vs corp) and nature of the business.  

I'm currently reorganizing and restructuring my rentals from being a sole-proprietor landlord to having an S-corp for managing properties.I just set up S-corp for managin the properties January 2017.

You tagged some other Michael  :)You can only have one EIN as a sole proprietor.

If you are a sole proprietor, your real estate business could do a profit share of up to 20% of your net business income - which is gross income, less expenses,. less 50% of self-employment taxes. 

As a sole proprietor, he could have all the liability and none of the rewards.

You get the new 20% deduction even if you own your business as an individual (sole proprietor).

Great question for your attorney @Stephanie Windemuth, but if the LLC is a sole-proprietor, you shouldn't have any issues, but great question for your attorney.