Yes Laurie, you can rollover IRA into Solo 401k.

I'm leaving my current employer soon and will be rolling over my 401k. I would like to roll it over to a self-directed 401k so I can potentially invest in real estate (ST/LT rentals). Does anyone have any recommended ...

yes, rollover or re-invest into real estate or decent REIT income producing yield.

@Manmath D.If your money is coming from a 401k I would suggest that you find a way to open a self directed solo 401k or qrp instead to roll over to.

For asset protection reasons, you might want to separate the asset holding entities (passive side & pass-through from taxation POV) from the public facing operations/property management shell entity (the active side & which can be taxed as S-corp if you want to create self-income for other purposes, like being able to establish Solo 401K and roll over other 401K and IRA funds for further investment options). 

Loan transactions take time, and won't always be frictionless. 

I currently have about 30K cash as a down payment but did not want to exhaust all of my cash, I also have money in my 401K that I could roll over to an SDIRA as well, please let me know your thoughts.  

Purchase agreement stated first lease will roll over to MTM and the other unit will be delivered empty at close.

My lender requested proof of CO to roll over my construction loan to the full loan for my duplex I built. 

If the ownership of the homes is the same as the ownership of the LLC then you can consider a roll over instead and still get the tax advantage.