Knowing you tile is important, because the cost to install penny tile is different than 12x12 sq, or if you are doing a complex pattern.  

I do manage some small apartment complexes and generally there are not too many issues, but not zero.Also, for me as a PM I have fixed costs per unit, so to have 5 listings in 1 house would be cost prohibitive.Just food for thought, good luck!

I have partial ownership of an apartment complex with several people.

These service providers recognize new investors like yourself are unable to articulate the risks they are  protecting against or how this is accomplished which leads to the upsell of complexed entity structures.

It appears that you have a complex structure already suggested to you(PM company, S-Corp, Investment LLC, etc).Who suggested this structure to you and what did they say was the benefit for setting all these companies up?

If you have tax planning and complex items within the return, I could see it getting there but it seems a little bit high.

Additionally, using a land trust with an LLC could offer protection without the complexity of multiple LLCs.

For your "BRRRR in Bulk" approach, you might want to explore lenders that specialize in portfolio or DSCR (Debt Service Coverage Ratio) loans, as they are often more flexible with complex financing structures like seller 2nd notes.

Maybe some affordable housing complexes. 

If you have the resources to buy a 150 unit apartment complex then again getting that done is a year is achievable.