You might want to read through the article at the link below. Note that you should be able to segregate your trading account from a non-trading account and, further, you will most likely gain little by organizing an LLC as a single-member LLC is disregarded for federal income tax purposes (although you could use an LLC to segregate your MTM trading activity).
https://www.thetaxadviser.com/issues/2010/feb/sec475mark-to-marketelection.html
