Returning Member

State tax filing

I think I have presented this question before but never received an answer.  My single member LLC purchased a property to flip 2/14/18. On 3/13/18 the agent/owner who sold me the property became a partner in the LLC.  The house was flipped 3/4/2019.  Due to differences of opinion as to documentation needed to pay 'requested' expenses and claim expenses on tax returns, he will be getting out of the LLC.  A final return is to be done within three months of his exit, so, will I use 2018 turbotax business or will 2019 be out by July/August 2018? Or maybe I should just get a CPA, since he received the full commission when I purchased the property and half of the commission when it was sold; so, he would not be eligible to expense the first commission and only eligible for half on the sale, whereas I should be able to expense both. Correct?  I'm sorry it's so complicated.