All 457's are Employer Sponsored thats the 1st requirement of the visa the e stands for Electronic not Employer.
Depending on how many points you have will depend on if you need the Employer Sponsorship to apply for PR.
It may also be faster if you get Employer Nomination, but if the employer wont do it (they want you on a 457 so you cant leave them) then you can go for State Sponsorship.
will give you information on both VISA's or you can go see a Migration Agent
Sounds like you are eligable for LAFTA but its up to the Employer to pay you that way, its not a right that you have, its a concession that can be offered to you by the Employer.