If you get a Work To Residence (WTR) visa (what you're calling the LTSSL, understandably from the heading on the page, but that name isn't a visa), it has a direct link to going to Residence if your circumstances are right after two years, as explained at the bottom of the page here, and on the further link.
http://www.immigration.govt.nz/migra...quirements.htm
The Temporary Work Visas, such as the Essential Skills one you're looking at, all have a limited life. When the visa is coming to an end, you have to apply to renew it, and that isn't a foregone conclusion, even if your employer wants to keep you. INZ review the Essential Skills Lists periodically, and if your skill is no longer in short supply in NZ, you could be refused a renewal. There is no direct link from one of these visas to Residence. You would have to apply separately under the Skilled Migrant Category.
http://www.immigration.govt.nz/migra...nt/default.htm
(Many people who get a temporary work visa so as to be able to start working soon when offered a job in NZ also apply under SMC for Residence at the same time. Much of the evidence can be used for the two applications, and they know their skill is wanted at this time. Once a migrant has Residence, the question of wanted skills is not going to be a problem for them.)
I
think the Essential Skills visa fee is listed under 'Talent'.