After getting my feet wet in investing over the last 5 years in NY and PA here is what I have come up with.
Set up your LLC(s) ahead of time, so when you purchase property you can have it titled to the LLC from the get go. It is costly (more so in PA that NY) to transfer afterwards. All that does is reduce your ROI. We're in this to make money, so get one set up and start using it. When you hit your equity threshold start another entity. For example. LLC A may hold 10 properties valued at 1MM, but which are leveraged at 90% LTV leaving 100,000 in equity that could be attacked. You can tweak that number depending on your personal risk tolerance.
I have had no problem getting landlord insurance for property titled in an LLC, the LLC members are named as additional insured.
I created an LLC to do the management and I have also created an LLC to do the repairs and maintenance. They are both multimember LLCs as opposed to single member. I give small percentages to various family members to prevent them from ever being lumped together in court. You want the companies to seem as different as possible. If they are all single member LLCs with just you, it won't really help. If they are all multimember LLCs with different people and different ownership percentages you'll be in much better shape IF anything ever happens.
The management company bills back a monthly fee to the owning entities and deals with lease ups, paper work, advertising, bill paying etc.
The construction company provides all repairs and maintenance and bills the owning entities directly.
Hope it helps!