We typically look for decent properties that are likely at the bottom of some bigger investor's portfolio.

When you have a VERIFIABLE record of success within specific property types - and typically specific geographical areas, you MAY be able to attract enough passive investment to begin syndicating smaller type deals.  

You can file paperwork yourself or as others have stated, hire an attorney.Typically, you'll want to have a notarized affidavit filed or writ of possession issued and signed by a judge.This can vary from jurisdictions so if you are unfamiliar with how to move forward it may be best to consult legal counsel.Legal counsel will typically cost in the low thousands after filing fees, processing fees, attorney fees, court costs, etc.

Also, what's the typical fee structure for single-family homes?

The suburbs in Philadelphia also great investments but typically the price points are a bit higher. 

Typically, unattended to small maintenance items will become bigger issues over time.

Typically, private lenders pay anywhere from $500 to $2,000 for loan documents, depending on the complexity of the deal and the attorney’s rates.

What are the typical fees that turnkey investors charge?  

A lender or appraiser will typically use the most recent MLS comps (for updated properties) in the area to determine ARV.

Fee for professional services are not typically based on the profit or value of the project.