I've read that some people will withhold the final 10% or so until all work is completed.

The problem is that a million people have registered companies with “holdings” or “investments” or “group” in the name.

He's withholding rent right now saying I need to cover half his bill since his heating costs are going towards the upper unit. 

Whether you’re within your rights as the managing member to withhold the information is immaterial in the grand scheme of things.

Most of the clients I've worked with as a Realtor are investors and I've already spoken to them about partnering up and helping out with the financial aspect (Hard money loans), I can handle finding the deals and working with the GC's.I am really excited to get started on my real estate investment project, but I am struggling with calculating the costs associated with holding the property.

Showing that you (the payer) are not withholding any taxes and that they are not a full time employee of yours. 

You can withhold a bit to show FL PM LLC earns something doing this, I would recommend that.

Our property management company in Philadelphia is withholding our rental income since we gave them notice to terminate our contract.

The foreign investor will likely be subject to the mandatory withholding required by FIRPTA, which absolutely will complicate a 1031 Exchange transaction, but can be addressed as long as the investor and his or her closing agents are proactive.The foreign investor must apply with the Internal Revenue Service for a ITIN number (if they do not already have a Social Security number or employer identification number), and then once obtained they must apply for a Certificate of Exemption for Withholding, which requires the submission of the Purchase and Sale Agreement/Contract for both the relinquished property and the replacement property.

If anyone has been through a similar situation please advise.Below is the hypothetical example he createdPerson has income from a job (W2) He and his spouse  have a LLC with holds their multiple real estate rental properties.