The $18k limit for elective deferrals to a 401(k) and the $18k limit for elective deferrals to a 457(b) are separate, independent limits, allowing you to defer $18k to each.
You do not "claim a deduction" for these unless you are self-employed with respect to these jobs. If you receive a W-2 from your employers, the employers will have already excluded from box 1 these amounts reported with codes E and G.
