Can 4” hole be cut in the joist for HVAC duct and reinforced the joist to strengthen it. 

This approach will also help you develop or strengthen your relationship with a realtor which is invaluable for real estate investing.  

The goal is to just keep strengthening the relationship by finding out whats new with them... what goals they've set, what action steps they're taking to meet those goals, and if/how you can help them achieve those goals.

I just need to strengthen my abilities to negotiate with the owners of the property so I can bring the best deals to you guys, but also allow me (in the future) to step in and do the rehabs too.  

But are there any other things I could bring up to help strengthen my position.Thanks,Anthony.

It will strengthen your relationship and produce remarkable results for you both.Don't sign an exclusive buyer's agency form and let each REA know that you are also working with other agents.

It is a nice touch and ensures that the relationship is strengthened.

That's why asking questions like these that Mike recommended strengthen your negotiating position.

You have to evaluate where your weaknesses are and determine a way to change processes and strengthen that area or hire someone that can handle it for you.

You hefty down payment only strengthens your application.