Need your expert suggestion on h1b interview

need your expert suggestion in my question :

My petition has approved. Planning to attend interview.
my company is very small consultancy and i suppose to work in house project but its not actually in house project, I will work for my employer and will provide unix support to my employer’s end clients from my employer’s premise.
I have valid contract agreement letter of end clients.

Will these contract agreement letter enough to support such type of work model?

Or Interviewer can ask more docs like sow, client letter etc?

Please suggest.