Commercial real estate - Pittsburg PA - Help

I am looking at a commercial office building in Pittsburg. Office Building is in good share, but on market for lease/Sell. Numbers look very good. So wanted to dig in to the deal. I am new to this space so couple of questions. 

1) Should i look for commercial real estate agent for this deal or any agent is fine? can the same agent help me on the du-diligence on the market, comps etc.

2) Would a bank be able to Loan on this with 25% down?

3) What are the Risks or things i should consider in the commercial space. I am new to this space. Any Advice  from experienced professional will be appreciated. The area rent at $16/SQFT/Year and the Sell cost is $70/SQFT.