Sniper - modifiers

If i want spot obscured sniper i should roll 6+ ? (obscured infantry 4+, sniper -1, infantry team of three men or less -1)

Yes, 6+.

He's a man trying very hard not to be seen. In the job description really.

Wait, people try to Aimed Fire at Snipers?

I thought Standard Practice for all sub-three-man units was to just Area Fire until they roll a '1' for their Cover Save...