Question about getting a loan for mixed use property (commercial & residential)

[William Than]

You may laugh at my ignorance but I need some advices, your help and knowledge are truly appreciated! 

I currently owe a mixed use property which has a commercial on the first floor and two residential units on the upper floors, i live in one of residential unit so that would consider an owner occupied property. My plan is to purchase another similar mixed use property, however I run short or the 25% required down payment for commercial loan. Here are my questions:

1. I want to take the equity of my current property for the down payment on the other, my current mortgage lender does not offer equity line of credit for mixed use property, the loan officer told me I may find some lenders offer that type of loan. How do I find out which lenders offer that program?

2. Is it possible to get a conventional residential loan for a mixed use property so i don't have to come up with the 25% down payment? How do I do that?

3. The property i am planning is not listed for sales, is there such thing as negotiation service for hire to help me to convince the owner to sell his property?

I really appreciate all the advices from everyone!