how to structure new RE biz-to use funds from solo 401k-LLC or S corp?

[Suzanne HAINER]

Hello! My sister and I are starting a real estate investment business which will initially be funded with our self directed solo 401k's and regular savings. Our goal will be to buy and sell to flippers or buy and flip ourselves at least 2 properties per year at first. We plan to buy at least one rental property per year for passive income. Initially, we thought an LLC was the way to go but a meeting with a seasoned RE agent and investor yesterday pointed us in the S-corp direction. Is there a difference between the 2 types when it comes to funding your transactions? We have a meeting with a business attorney next week but want to be as educated as possible before that. Thank you to all who take the time to give advice!!!