I am wondering if the job requires B.S + 5 yrs exp + License requirement, will it be classified as wage level 3? I also heard that if the job tittle has "senior" or "lead", it will automatically classified as wage level 3? Is this correct?
Will the prevailing wage include benefit and bonus or it is just base salary? I heard it is just base salary but would like to confirm.
As a practical matter, this is probably correct even though that isn't how the rule is worded. The guidelines for determining level do specify that both level of degree & experience required as well as supervision of others are considerations in making the determination. See pages 6 and 7 of this document: http://www.foreignlaborcert.doleta.gov/pdf/NPWHC_Guidance_Revised_11_2009.pdf for an explanation; note that Level 3 mentions that they should consider "key words" that define supervisory responsibilities.
Prevailing wage encompasses base salary alone - you are correct. The value of Benefits isn't included, and bonus can't be counted because it isn't a guaranteed component of compensation (a bonus is something that isn't promised in any specific amount, even if there is a normal range).
Speak with an attorney for further guidance on your case.