Hi @Adam Burrows, wanted to give my 2 cents from an estate planning/asset protection background. If I'm following this correctly, the 1st issue I see is that you have an "active" business (consulting) versus a "passive" business (the rental property, assuming you don't do hands on management, etc.)...this would be a separating line for many people I've talked to about this. From an exposure to liability, in the sense of how much a party can be responsible for action/inaction can come down to the participation for that business.
The 2nd issue is that your consulting business income is going into your personal checking account, and not the bank account tied to the LLC which (presumably) owns your consulting business. Whichever LLC you have the consulting business in, is not doing anything much for you because of the comingling of funds into your personal account. Now mind you, depending on what type of consulting you are in, your exposure to liability from that business activity may be very limited, thus, a sole proprietor may be fine.
3rd issue, where would the rents to your property be deposited to? You mentioned you wouldn't have it go in the LLC which you would form for that rental property. (Again, you could be comingling, depending on what your plan was for this).
4th issue, in trying to keep the existing parent LLC functional for potentially both, it makes it unclear the purpose of the LLC in the first place (this is something typically indicated clearly in your Operating Agreement, assuming you have one).
LLCs can provide great asset protection (contrary to what many may say or believe), BUT...big BUT here, it must be set up correctly and maintained correctly. I'll say that again, it must be maintained correctly. This means you have an LLC for a single business activity, which is filed correctly, has an Operating Agreement with clear and precise terms, you set up a separate bank account for that LLC and its related business activity, you do not use that bank account in any way for personal activity, and while it varies per state as being a requirement, you always want to make sure you have periodic filings and to take it even further, hold a "meeting" once a year...even if you're the sole member and there's not much changes that took place for the year. This is all to show to a Court and a savvy plaintiff attorney (when you get sued) that your business activities follow corporate formalities and they are separate from you as an individual.
I see why many of us on BP want to keep admin work to a minimum and reduce the necessity of extra entities and extra bank accounts, but these are things that the big players do. And while I'm certainly not there yet in terms of real estate, I know that any hiccups in my acquisitions and scaling up won't come from a lapse in my asset protection structure.
I hope this helps! Feel free to ask away..