Our agent has repeatedly said that the selling agent has been difficult to work with and has suggested that if we do not get the information we are asking for that it might be in our best interest to walk away.We don't want to put down earnest money and pay for an inspection until this information has been provided.

I found it on MLS, negotiated a decent price, then renegotiated after the inspection found a significant water leak and related damage.

Will I need to get a formal "home inspection" (which seems prudent), what should I do specifically with relation to my new mobile home?  

But you should still always insist on estoppel letters and right to inspect and approve all active lease agreements, and insist that there are no "side" agreements other than what are disclosed to you for approval after the purchase contract is signed.

I am currently in the process of having the house inspected by both an inspector and my contractor.

To actually make an offer I just call my realtor and tell her how much money, date of closing and any contingencies I want such as inspection. 

The real difference from the things you're describing is the difficulty in inspecting the lines exact condition, it's not like a roof or windows at all.

- dose appraisal process require home inspection ?

The homes are in move-in ready condition i.e. no rehab required or no major issues uncovered in the inspection report?

Be prepared to pay inspection and appraisal upfront and commercial appraisal aren’t cheap.